diff --git a/.gitignore b/.gitignore
index 8f6fc3c8dd..e3764d839f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ jitwatch.out
 .settings
 .project
 .gradle
+.kotlin
 .vscode
 .idea
 *.iml
diff --git a/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java b/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java
index 3d5d2314f2..20a71a3da1 100644
--- a/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java
+++ b/caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java
@@ -3163,6 +3163,7 @@ <T> T expireAfterAccessOrder(boolean oldest, Function<@Nullable V, @Nullable V>
    * @param mappingFunction the mapping function to compute a value
    * @return the computed value
    */
+  @SuppressWarnings("NullAway")
   <T> T snapshot(Iterable<Node<K, V>> iterable, Function<@Nullable V, @Nullable V> transformer,
       Function<Stream<CacheEntry<K, V>>, T> mappingFunction) {
     requireNonNull(mappingFunction);
@@ -4009,6 +4010,7 @@ static final class BoundedPolicy<K, V> implements Policy<K, V> {
     @Override public @Nullable V getIfPresentQuietly(K key) {
       return transformer.apply(cache.getIfPresentQuietly(key));
     }
+    @SuppressWarnings("NullAway")
     @Override public @Nullable CacheEntry<K, V> getEntryIfPresentQuietly(K key) {
       Node<K, V> node = cache.data.get(cache.nodeFactory.newLookupKey(key));
       return (node == null) ? null : cache.nodeToCacheEntry(node, transformer);
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncAsMapTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncAsMapTest.java
index 57dd96cb68..7f6968ca19 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncAsMapTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncAsMapTest.java
@@ -28,6 +28,7 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
@@ -292,8 +293,8 @@ public void put_insert(AsyncCache<Int, Int> cache, CacheContext context) {
   public void put_replace_sameValue(AsyncCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, Int>();
     for (Int key : context.firstMiddleLastKeys()) {
-      var oldValue = cache.asMap().get(key);
-      var value = cache.asMap().get(key).thenApply(val -> intern(new Int(val)));
+      var oldValue = requireNonNull(cache.asMap().get(key));
+      var value = oldValue.thenApply(val -> intern(new Int(val)));
       assertThat(cache.asMap().put(key, value)).isSameInstanceAs(oldValue);
       assertThat(cache).containsEntry(key, value);
       replaced.put(key, context.original().get(key));
@@ -307,7 +308,7 @@ public void put_replace_sameValue(AsyncCache<Int, Int> cache, CacheContext conte
   @CacheSpec(population = { Population.SINGLETON, Population.PARTIAL, Population.FULL })
   public void put_replace_sameInstance(AsyncCache<Int, Int> cache, CacheContext context) {
     for (Int key : context.firstMiddleLastKeys()) {
-      var value = cache.asMap().get(key);
+      var value = requireNonNull(cache.asMap().get(key));
       assertThat(cache.asMap().put(key, value)).isSameInstanceAs(value);
       assertThat(cache).containsEntry(key, value);
     }
@@ -435,7 +436,7 @@ public void putIfAbsent_nullKeyAndValue(AsyncCache<Int, Int> cache, CacheContext
   removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void putIfAbsent_present(AsyncCache<Int, Int> cache, CacheContext context) {
     for (Int key : context.firstMiddleLastKeys()) {
-      var value = cache.asMap().get(key);
+      var value = requireNonNull(cache.asMap().get(key));
       assertThat(cache.asMap().putIfAbsent(key, key.asFuture())).isEqualTo(value);
       assertThat(cache).containsEntry(key, value);
     }
@@ -589,8 +590,8 @@ public void replace_failure(AsyncCache<Int, Int> cache, CacheContext context) {
   public void replace_sameValue(AsyncCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, Int>();
     for (Int key : context.firstMiddleLastKeys()) {
-      var oldValue = cache.asMap().get(key);
-      var newValue = cache.asMap().get(key).thenApply(val -> intern(new Int(val)));
+      var oldValue = requireNonNull(cache.asMap().get(key));
+      var newValue = oldValue.thenApply(val -> intern(new Int(val)));
       assertThat(cache.asMap().replace(key, newValue)).isSameInstanceAs(oldValue);
       assertThat(cache).containsEntry(key, newValue);
       replaced.put(key, context.original().get(key));
@@ -718,8 +719,8 @@ public void replaceConditionally_wrongOldValue(AsyncCache<Int, Int> cache, Cache
   public void replaceConditionally_sameValue(AsyncCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, Int>();
     for (Int key : context.firstMiddleLastKeys()) {
-      var oldValue = cache.asMap().get(key);
-      var newValue = cache.asMap().get(key).thenApply(val -> intern(new Int(val)));
+      var oldValue = requireNonNull(cache.asMap().get(key));
+      var newValue = oldValue.thenApply(val -> intern(new Int(val)));
       assertThat(cache.asMap().replace(key, oldValue, newValue)).isTrue();
       assertThat(cache).containsEntry(key, newValue);
       replaced.put(key, context.original().get(key));
@@ -1310,7 +1311,7 @@ public void merge_absent(AsyncCache<Int, Int> cache, CacheContext context) {
   public void merge_sameValue(AsyncCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, CompletableFuture<Int>>();
     for (Int key : context.firstMiddleLastKeys()) {
-      var value = cache.asMap().get(key).thenApply(Int::new);
+      var value = requireNonNull(cache.asMap().get(key)).thenApply(Int::new);
       var result = cache.asMap().merge(key, key.negate().asFuture(), (oldValue, v) -> value);
       assertThat(result).isSameInstanceAs(value);
       replaced.put(key, value);
@@ -1566,7 +1567,9 @@ public void keySet_removeAll_partial(AsyncCache<Int, Int> cache, CacheContext co
     assertThat(cache.asMap().keySet().removeAll(context.firstMiddleLastKeys())).isTrue();
     assertThat(cache.synchronous().asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -1739,7 +1742,9 @@ public void keySet_retainAll_partial(AsyncCache<Int, Int> cache, CacheContext co
     assertThat(cache.asMap().keySet().retainAll(expected.keySet())).isTrue();
     assertThat(cache.asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -1872,6 +1877,7 @@ public void keySpliterator_estimateSize(AsyncCache<Int, Int> cache, CacheContext
   /* ---------------- Values -------------- */
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void values_toArray_null(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -1978,12 +1984,15 @@ public void values_removeAll_none_populated(AsyncCache<Int, Int> cache, CacheCon
   public void values_removeAll_partial(AsyncCache<Int, Int> cache, CacheContext context) {
     var expected = new HashMap<>(context.original());
     expected.keySet().removeAll(context.firstMiddleLastKeys());
-    var removed = Maps.asMap(context.firstMiddleLastKeys(), cache.asMap()::get);
+    var removed = Maps.asMap(context.firstMiddleLastKeys(),
+        key -> requireNonNull(cache.asMap().get(key)));
 
     assertThat(cache.asMap().values().removeAll(removed.values())).isTrue();
     assertThat(cache.synchronous().asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -2026,7 +2035,7 @@ public void values_remove_none(AsyncCache<Int, Int> cache, CacheContext context)
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL)
   public void values_remove(AsyncCache<Int, Int> cache, CacheContext context) {
-    var future = cache.asMap().get(context.firstKey());
+    var future = requireNonNull(cache.asMap().get(context.firstKey()));
     assertThat(cache.asMap().values().remove(future)).isTrue();
     var expected = new HashMap<>(context.original());
     expected.remove(context.firstKey());
@@ -2167,7 +2176,9 @@ public void values_retainAll_partial(AsyncCache<Int, Int> cache, CacheContext co
     assertThat(cache.asMap().values().retainAll(expected.values())).isTrue();
     assertThat(cache.asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -2438,14 +2449,17 @@ public void entrySet_removeAll_none_populated(AsyncCache<Int, Int> cache, CacheC
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL)
   public void entrySet_removeAll_partial(AsyncCache<Int, Int> cache, CacheContext context) {
-    var removed = Maps.asMap(context.firstMiddleLastKeys(), cache.asMap()::get);
+    var removed = Maps.asMap(context.firstMiddleLastKeys(),
+        key -> requireNonNull(cache.asMap().get(key)));
     var expected = new HashMap<>(context.original());
     expected.keySet().removeAll(removed.keySet());
 
     assertThat(cache.asMap().entrySet().removeAll(removed.entrySet())).isTrue();
     assertThat(cache.synchronous().asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -2656,7 +2670,9 @@ public void entrySet_retainAll_partial(AsyncCache<Int, Int> cache, CacheContext
     assertThat(cache.asMap().entrySet().retainAll(expected.entrySet())).isTrue();
     assertThat(cache.asMap()).isEqualTo(expected);
     assertThat(context).removalNotifications().withCause(EXPLICIT)
-        .contains(Maps.asMap(context.firstMiddleLastKeys(), context.original()::get)).exclusively();
+        .contains(Maps.asMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncCacheTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncCacheTest.java
index 908b1b6157..c66fd42a0b 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncCacheTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncCacheTest.java
@@ -29,6 +29,7 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
@@ -85,6 +86,7 @@ public final class AsyncCacheTest {
 
   /* --------------- getIfPresent --------------- */
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getIfPresent_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -111,12 +113,14 @@ public void getIfPresent_present(AsyncCache<Int, Int> cache, CacheContext contex
   /* --------------- getFunc --------------- */
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getFunc_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThrows(NullPointerException.class, () -> cache.get(null, key -> null));
   }
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getFunc_nullLoader(AsyncCache<Int, Int> cache, CacheContext context) {
     Function<Int, Int> mappingFunction = null;
@@ -124,6 +128,7 @@ public void getFunc_nullLoader(AsyncCache<Int, Int> cache, CacheContext context)
   }
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getFunc_nullKeyAndLoader(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThrows(NullPointerException.class, () -> cache.get(null, (Function<Int, Int>) null));
@@ -133,6 +138,7 @@ public void getFunc_nullKeyAndLoader(AsyncCache<Int, Int> cache, CacheContext co
   @Test(dataProvider = "caches")
   public void getFunc_absent_null(AsyncCache<Int, Int> cache, CacheContext context) {
     Int key = context.absentKey();
+    @SuppressWarnings("NullAway")
     var valueFuture = cache.get(key, k -> null);
     assertThat(context).stats().hits(0).misses(1).success(0).failures(1);
 
@@ -146,6 +152,7 @@ public void getFunc_absent_null_async(AsyncCache<Int, Int> cache, CacheContext c
     Int key = context.absentKey();
     var ready = new AtomicBoolean();
     var done = new AtomicBoolean();
+    @SuppressWarnings("NullAway")
     var valueFuture = cache.get(key, k -> {
       await().untilTrue(ready);
       return null;
@@ -201,6 +208,7 @@ public void getFunc_absent_failure_async(AsyncCache<Int, Int> cache, CacheContex
   @CacheSpec(executor = CacheExecutor.THREADED, executorFailure = ExecutorFailure.IGNORED)
   public void getFunc_absent_cancelled(AsyncCache<Int, Int> cache, CacheContext context) {
     var done = new AtomicBoolean();
+    @SuppressWarnings("NullAway")
     var valueFuture = cache.get(context.absentKey(), k -> {
       await().until(done::get);
       return null;
@@ -241,6 +249,7 @@ public void getFunc_present(AsyncCache<Int, Int> cache, CacheContext context) {
   /* --------------- getBiFunc --------------- */
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getBiFunc_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThrows(NullPointerException.class, () ->
@@ -248,6 +257,7 @@ public void getBiFunc_nullKey(AsyncCache<Int, Int> cache, CacheContext context)
   }
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getBiFunc_nullLoader(AsyncCache<Int, Int> cache, CacheContext context) {
     BiFunction<Int, Executor, CompletableFuture<Int>> mappingFunction = null;
@@ -255,6 +265,7 @@ public void getBiFunc_nullLoader(AsyncCache<Int, Int> cache, CacheContext contex
   }
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getBiFunc_nullKeyAndLoader(AsyncCache<Int, Int> cache, CacheContext context) {
     BiFunction<Int, Executor, CompletableFuture<Int>> mappingFunction = null;
@@ -372,6 +383,7 @@ public void getBiFunc_present(AsyncCache<Int, Int> cache, CacheContext context)
   /* --------------- getAllFunc --------------- */
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllFunction_nullKeys(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -380,6 +392,7 @@ public void getAllFunction_nullKeys(AsyncCache<Int, Int> cache, CacheContext con
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllFunction_nullKeys_nullFunction(
@@ -389,6 +402,7 @@ public void getAllFunction_nullKeys_nullFunction(
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllFunction_nullFunction(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -413,6 +427,7 @@ public void getAllFunction_iterable_empty(AsyncCache<Int, Int> cache, CacheConte
     assertThat(result).isExhaustivelyEmpty();
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllFunction_nullLookup(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -443,6 +458,7 @@ public void getAllFunction_immutable_result(AsyncCache<Int, Int> cache, CacheCon
   }
 
   @CacheSpec
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   public void getAllFunction_absent_null(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThat(cache.getAll(context.absentKeys(), keys -> null))
@@ -609,6 +625,7 @@ public void getAllFunction_canceled_individual(AsyncCache<Int, Int> cache, Cache
     });
     for (var key : context.absentKeys()) {
       var future = cache.getIfPresent(key);
+      requireNonNull(future);
       future.cancel(true);
       assertThat(future).hasCompletedExceptionally();
     }
@@ -655,6 +672,7 @@ public void getAllFunction_badLoader(AsyncCache<Int, Int> cache, CacheContext co
   /* --------------- getAllBiFunc --------------- */
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllBifunction_nullKeys(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -663,6 +681,7 @@ public void getAllBifunction_nullKeys(AsyncCache<Int, Int> cache, CacheContext c
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllBifunction_nullKeys_nullBifunction(
@@ -672,6 +691,7 @@ public void getAllBifunction_nullKeys_nullBifunction(
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void getAllBifunction_nullBifunction(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -938,6 +958,7 @@ public void getAllBifunction_canceled_individual(
     });
     for (var key : context.absentKeys()) {
       var future = cache.getIfPresent(key);
+      requireNonNull(future);
       future.cancel(true);
       assertThat(future).hasCompletedExceptionally();
     }
@@ -1010,6 +1031,7 @@ public void getAllBifunction_early_success(AsyncCache<Int, Int> cache, CacheCont
     var result = cache.getAll(context.absentKeys(), (keysToLoad, executor) -> bulk);
     var future = cache.asMap().get(key);
 
+    requireNonNull(future);
     future.complete(value);
     bulk.complete(context.absent()); // obtrudes the future's value
 
@@ -1027,6 +1049,8 @@ public void getAllBifunction_early_failure(AsyncCache<Int, Int> cache, CacheCont
     var bulk = new CompletableFuture<Map<Int, Int>>();
     var result = cache.getAll(context.absentKeys(), (keysToLoad, executor) -> bulk);
     var future = cache.asMap().get(key);
+
+    requireNonNull(future);
     future.completeExceptionally(error);
 
     bulk.complete(context.absent());
@@ -1043,6 +1067,7 @@ public void getAllBifunction_early_failure(AsyncCache<Int, Int> cache, CacheCont
 
   /* --------------- put --------------- */
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void put_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
@@ -1050,12 +1075,14 @@ public void put_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThrows(NullPointerException.class, () -> cache.put(null, value));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void put_nullValue(AsyncCache<Int, Int> cache, CacheContext context) {
     assertThrows(NullPointerException.class, () -> cache.put(context.absentKey(), null));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void put_nullKeyAndValue(AsyncCache<Int, Int> cache, CacheContext context) {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/BoundedLocalCacheTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/BoundedLocalCacheTest.java
index 42d54382ab..a03be45ef8 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/BoundedLocalCacheTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/BoundedLocalCacheTest.java
@@ -998,8 +998,13 @@ public void evict_retired_victim(BoundedLocalCache<Int, Int> cache, CacheContext
 
   @Test(dataProvider = "caches")
   @CacheSpec(compute = Compute.SYNC, population = Population.EMPTY,
-      maximumSize = Maximum.FULL, weigher = CacheWeigher.VALUE)
+      maximumSize = Maximum.FULL, weigher = CacheWeigher.MOCKITO)
   public void evict_zeroWeight_candidate(BoundedLocalCache<Int, Int> cache, CacheContext context) {
+    when(context.weigher().weigh(any(), any())).thenAnswer(invocation -> {
+      Int value = invocation.getArgument(1);
+      return Math.abs(value.intValue());
+    });
+
     for (int i = 0; i < context.maximumSize(); i++) {
       assertThat(cache.put(Int.valueOf(i), Int.valueOf(1))).isNull();
     }
@@ -1019,8 +1024,13 @@ public void evict_zeroWeight_candidate(BoundedLocalCache<Int, Int> cache, CacheC
 
   @Test(dataProvider = "caches")
   @CacheSpec(compute = Compute.SYNC, population = Population.EMPTY,
-      maximumSize = Maximum.FULL, weigher = CacheWeigher.VALUE)
+      maximumSize = Maximum.FULL, weigher = CacheWeigher.MOCKITO)
   public void evict_zeroWeight_victim(BoundedLocalCache<Int, Int> cache, CacheContext context) {
+    when(context.weigher().weigh(any(), any())).thenAnswer(invocation -> {
+      Int value = invocation.getArgument(1);
+      return Math.abs(value.intValue());
+    });
+
     for (int i = 0; i < context.maximumSize(); i++) {
       assertThat(cache.put(Int.valueOf(i), Int.valueOf(1))).isNull();
     }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineSpecGuavaTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineSpecGuavaTest.java
index aa2b2fc4dd..4b01a97910 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineSpecGuavaTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineSpecGuavaTest.java
@@ -354,21 +354,25 @@ public void testEqualsAndHashCode() {
         .testEquals();
   }
 
+  @SuppressWarnings("NullAway")
   public void testMaximumWeight_withWeigher() {
     Caffeine<Object, Object> builder = Caffeine.from(parse("maximumWeight=9000"));
     assertThat(builder.weigher((k, v) -> 42).build(k -> null)).isNotNull();
   }
 
+  @SuppressWarnings("NullAway")
   public void testMaximumWeight_withoutWeigher() {
     Caffeine<Object, Object> builder = Caffeine.from(parse("maximumWeight=9000"));
     assertThrows(IllegalStateException.class, () -> builder.build(k -> null));
   }
 
+  @SuppressWarnings("NullAway")
   public void testMaximumSize_withWeigher() {
     Caffeine<Object, Object> builder = Caffeine.from(parse("maximumSize=9000"));
     assertThat(builder.weigher((k, v) -> 42).build(k -> null)).isNotNull();
   }
 
+  @SuppressWarnings("NullAway")
   public void testMaximumSize_withoutWeigher() {
     Caffeine<Object, Object> builder = Caffeine.from(parse("maximumSize=9000"));
     assertThat(builder.build(k -> null)).isNotNull();
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineTest.java
index 7bd8d5d09f..fcc312a5db 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/CaffeineTest.java
@@ -28,13 +28,11 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
+import org.mockito.Mockito;
 import org.testng.annotations.AfterMethod;
-import org.testng.annotations.BeforeClass;
-import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
 
+import com.github.benmanes.caffeine.cache.stats.CacheStats;
 import com.github.benmanes.caffeine.cache.stats.StatsCounter;
 import com.github.benmanes.caffeine.cache.testing.CacheContext;
 import com.github.benmanes.caffeine.cache.testing.CacheProvider;
@@ -56,16 +54,11 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 public final class CaffeineTest {
-  @Mock StatsCounter statsCounter;
-  @Mock Expiry<Object, Object> expiry;
-  @Mock CacheLoader<Object, Object> loader;
+  private static final CacheLoader<Object, Object> loader = new FatalCacheLoader();
+  private static final StatsCounter statsCounter = new FatalStatsCounter();
+  private static final Expiry<Object, Object> expiry = new FatalExpiry();
 
-  @BeforeClass
-  public void beforeClass() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
-  }
-
-  @BeforeMethod @AfterMethod
+  @AfterMethod
   public void reset() {
     TestLoggerFactory.clear();
   }
@@ -104,6 +97,7 @@ public void configured() {
   }
 
   @Test
+  @SuppressWarnings("NullAway")
   public void fromSpec_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.from((CaffeineSpec) null));
   }
@@ -126,6 +120,7 @@ public void fromSpec() {
   }
 
   @Test
+  @SuppressWarnings("NullAway")
   public void fromString_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.from((String) null));
   }
@@ -196,6 +191,7 @@ public void calculateHashMapCapacity() {
   /* --------------- loading --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void loading_nullLoader() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().build(null));
   }
@@ -224,6 +220,7 @@ public void async_weakKeys_evictionListener() {
   /* --------------- async loader --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void asyncLoader_nullLoader() {
     assertThrows(NullPointerException.class, () ->
         Caffeine.newBuilder().buildAsync((CacheLoader<Object, Object>) null));
@@ -377,6 +374,7 @@ public void maximumWeight_large() {
   /* --------------- weigher --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void weigher_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().weigher(null));
   }
@@ -589,6 +587,7 @@ public void expireAfterWrite_duration_excessive() {
   /* --------------- expiry --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void expireAfter_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().expireAfter(null));
   }
@@ -744,6 +743,7 @@ public void softValues() {
   /* --------------- scheduler --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void scheduler_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().scheduler(null));
   }
@@ -773,6 +773,7 @@ public void scheduler_custom() {
   /* --------------- executor --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void executor_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().executor(null));
   }
@@ -793,6 +794,7 @@ public void executor() {
   /* --------------- ticker --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void ticker_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().ticker(null));
   }
@@ -815,6 +817,7 @@ public void ticker() {
   /* --------------- stats --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void recordStats_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().recordStats(null));
   }
@@ -838,9 +841,19 @@ public void recordStats() {
 
   @Test
   public void recordStats_custom() {
-    Supplier<StatsCounter> supplier = () -> statsCounter;
-    var builder = Caffeine.newBuilder().recordStats(supplier);
-    builder.statsCounterSupplier.get().recordEviction(1, RemovalCause.SIZE);
+    StatsCounter statsCounter = Mockito.mock();
+    var builder = Caffeine.newBuilder().recordStats(() -> statsCounter);
+    assertThat(builder.statsCounterSupplier).isNotNull();
+
+    var counter1 = builder.statsCounterSupplier.get();
+    var counter2 = builder.statsCounterSupplier.get();
+    assertThat(counter1).isNotSameInstanceAs(counter2);
+    assertThat(counter1).isNotNull();
+    assertThat(counter2).isNotNull();
+
+    assertThat(counter1.getClass().getName())
+        .isEqualTo("com.github.benmanes.caffeine.cache.stats.GuardedStatsCounter");
+    counter1.recordEviction(1, RemovalCause.SIZE);
     verify(statsCounter).recordEviction(1, RemovalCause.SIZE);
     assertThat(builder.build()).isNotNull();
   }
@@ -848,6 +861,7 @@ public void recordStats_custom() {
   /* --------------- removalListener --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void removalListener_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().removalListener(null));
   }
@@ -869,6 +883,7 @@ public void removalListener() {
   /* --------------- evictionListener --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void evictionListener_null() {
     assertThrows(NullPointerException.class, () -> Caffeine.newBuilder().evictionListener(null));
   }
@@ -886,4 +901,45 @@ public void evictionListener() {
     assertThat(builder.evictionListener).isSameInstanceAs(removalListener);
     assertThat(builder.build()).isNotNull();
   }
+
+  private static final class FatalCacheLoader implements CacheLoader<Object, Object> {
+    @Override public Object load(Object key) throws Exception {
+      throw new AssertionError();
+    }
+  }
+
+  private static final class FatalExpiry implements Expiry<Object, Object> {
+    @Override public long expireAfterCreate(Object key, Object value, long currentTime) {
+      throw new AssertionError();
+    }
+    @Override public long expireAfterUpdate(Object key, Object value,
+        long currentTime, long currentDuration) {
+      throw new AssertionError();
+    }
+    @Override public long expireAfterRead(Object key, Object value,
+        long currentTime, long currentDuration) {
+      throw new AssertionError();
+    }
+  }
+
+  private static final class FatalStatsCounter implements StatsCounter {
+    @Override public void recordHits(int count) {
+      throw new AssertionError();
+    }
+    @Override public void recordMisses(int count) {
+      throw new AssertionError();
+    }
+    @Override public void recordLoadSuccess(long loadTime) {
+      throw new AssertionError();
+    }
+    @Override public void recordLoadFailure(long loadTime) {
+      throw new AssertionError();
+    }
+    @Override public void recordEviction(int weight, RemovalCause cause) {
+      throw new AssertionError();
+    }
+    @Override public CacheStats snapshot() {
+      throw new AssertionError();
+    }
+  }
 }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/EvictionTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/EvictionTest.java
index ca451325d4..e72fe319fe 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/EvictionTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/EvictionTest.java
@@ -1199,12 +1199,14 @@ public void coldest_snapshot(Cache<Int, Int> cache,
     assertThat(coldest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(initialCapacity = InitialCapacity.EXCESSIVE, maximumSize = Maximum.FULL)
   public void coldestFunc_null(CacheContext context, Eviction<Int, Int> eviction) {
     assertThrows(NullPointerException.class, () -> eviction.coldest(null));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(initialCapacity = InitialCapacity.EXCESSIVE, maximumSize = Maximum.FULL)
   public void coldestFunc_nullResult(CacheContext context, Eviction<Int, Int> eviction) {
@@ -1404,12 +1406,14 @@ public void hottest_snapshot(Cache<Int, Int> cache,
     assertThat(hottest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(initialCapacity = InitialCapacity.EXCESSIVE, maximumSize = Maximum.FULL)
   public void hottestFunc_null(CacheContext context, Eviction<Int, Int> eviction) {
     assertThrows(NullPointerException.class, () -> eviction.hottest(null));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(initialCapacity = InitialCapacity.EXCESSIVE, maximumSize = Maximum.FULL)
   public void hottestFunc_nullResult(CacheContext context, Eviction<Int, Int> eviction) {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterVarTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterVarTest.java
index d447b056c6..8c2579cf71 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterVarTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterVarTest.java
@@ -34,6 +34,7 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
@@ -57,6 +58,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiFunction;
 
+import org.jspecify.annotations.Nullable;
 import org.mockito.Mockito;
 import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
@@ -961,6 +963,7 @@ public void setExpiresAfter_expired(Cache<Int, Int> cache,
   /* --------------- Policy: putIfAbsent --------------- */
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -971,6 +974,7 @@ public void putIfAbsent_nullKey(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -981,6 +985,7 @@ public void putIfAbsent_nullValue(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1001,6 +1006,7 @@ public void putIfAbsent_negativeDuration(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1062,6 +1068,7 @@ public void putIfAbsent_present(Cache<Int, Int> cache,
   /* --------------- Policy: put --------------- */
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1072,6 +1079,7 @@ public void put_nullKey(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1082,6 +1090,7 @@ public void put_nullValue(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1115,6 +1124,7 @@ public void put_excessiveDuration(Cache<Int, Int> cache,
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(population = Population.FULL,
       expiry = CacheExpiry.WRITE, expiryTime = Expire.ONE_MINUTE)
@@ -1162,6 +1172,7 @@ public void put_replace(Cache<Int, Int> cache,
 
   /* --------------- Policy: compute --------------- */
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS, removalListener = {Listener.DISABLED, Listener.REJECTING})
   public void compute_nullKey(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
@@ -1170,6 +1181,7 @@ public void compute_nullKey(CacheContext context, VarExpiration<Int, Int> expire
   }
 
   @CheckNoStats
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS, removalListener = {Listener.DISABLED, Listener.REJECTING})
   public void compute_nullMappingFunction(CacheContext context,
@@ -1227,8 +1239,8 @@ public void compute_remove(Cache<Int, Int> cache,
   @SuppressWarnings("CheckReturnValue")
   @CacheSpec(expiry = CacheExpiry.ACCESS)
   public void compute_recursive(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
-    var mappingFunction = new BiFunction<Int, Int, Int>() {
-      @Override public Int apply(Int key, Int value) {
+    var mappingFunction = new BiFunction<Int, Int, @Nullable Int>() {
+      @Override public @Nullable Int apply(Int key, Int value) {
         return expireAfterVar.compute(key, this, Duration.ofDays(1));
       }
     };
@@ -1243,8 +1255,8 @@ public void compute_recursive(CacheContext context, VarExpiration<Int, Int> expi
   public void compute_pingpong(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
     var key1 = Int.valueOf(1);
     var key2 = Int.valueOf(2);
-    var mappingFunction = new BiFunction<Int, Int, Int>() {
-      @Override public Int apply(Int key, Int value) {
+    var mappingFunction = new BiFunction<Int, Int, @Nullable Int>() {
+      @Override public @Nullable Int apply(Int key, Int value) {
         return expireAfterVar.compute(key.equals(key1) ? key2 : key1, this, Duration.ofDays(1));
       }
     };
@@ -1416,7 +1428,7 @@ public void compute_differentValue(Cache<Int, Int> cache,
     var replaced = new HashMap<Int, Int>();
     var duration = context.expiryTime().duration().dividedBy(2);
     for (Int key : context.firstMiddleLastKeys()) {
-      Int value = context.original().get(key);
+      Int value = requireNonNull(context.original().get(key));
       Int result = expireAfterVar.compute(key, (k, v) -> value.negate(), duration);
 
       replaced.put(key, value);
@@ -1679,12 +1691,14 @@ public void oldest_snapshot(Cache<Int, Int> cache,
     assertThat(oldest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS)
   public void oldestFunc_null(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
     assertThrows(NullPointerException.class, () -> expireAfterVar.oldest(null));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS)
   public void oldestFunc_nullResult(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
@@ -1819,12 +1833,14 @@ public void youngest_snapshot(Cache<Int, Int> cache,
     assertThat(youngest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS)
   public void youngestFunc_null(CacheContext context, VarExpiration<Int, Int> expireAfterVar) {
     assertThrows(NullPointerException.class, () -> expireAfterVar.youngest(null));
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expiry = CacheExpiry.ACCESS)
   public void youngestFunc_nullResult(CacheContext context,
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterWriteTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterWriteTest.java
index 2f3ee7914f..d7313dbe15 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterWriteTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterWriteTest.java
@@ -27,6 +27,7 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static org.junit.Assert.assertThrows;
 import static org.slf4j.event.Level.WARN;
 
@@ -94,7 +95,7 @@ public void getIfPresent(Cache<Int, Int> cache, CacheContext context) {
       mustExpireWithAnyOf = { AFTER_WRITE, VARIABLE }, expireAfterWrite = Expire.ONE_MINUTE,
       expiry = { CacheExpiry.DISABLED, CacheExpiry.WRITE }, expiryTime = Expire.ONE_MINUTE)
   public void get(Cache<Int, Int> cache, CacheContext context) {
-    Function<Int, Int> mappingFunction = context.original()::get;
+    Function<Int, Int> mappingFunction = key -> requireNonNull(context.original().get(key));
     context.ticker().advance(Duration.ofSeconds(30));
     var value = cache.get(context.firstKey(), mappingFunction);
     assertThat(value).isEqualTo(context.original().get(context.firstKey()));
@@ -395,6 +396,7 @@ public void oldest_snapshot(Cache<Int, Int> cache, CacheContext context,
     assertThat(oldest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expireAfterWrite = Expire.ONE_MINUTE)
   public void oldestFunc_null(CacheContext context,
@@ -406,6 +408,7 @@ public void oldestFunc_null(CacheContext context,
   @CacheSpec(expireAfterWrite = Expire.ONE_MINUTE)
   public void oldestFunc_nullResult(CacheContext context,
       @ExpireAfterWrite FixedExpiration<Int, Int> expireAfterWrite) {
+    @SuppressWarnings("NullAway")
     var result = expireAfterWrite.oldest(stream -> null);
     assertThat(result).isNull();
   }
@@ -544,6 +547,7 @@ public void youngest_snapshot(Cache<Int, Int> cache, CacheContext context,
     assertThat(youngest).containsExactlyEntriesIn(context.original());
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "caches")
   @CacheSpec(expireAfterWrite = Expire.ONE_MINUTE)
   public void youngestFunc_null(CacheContext context,
@@ -555,6 +559,7 @@ public void youngestFunc_null(CacheContext context,
   @CacheSpec(expireAfterWrite = Expire.ONE_MINUTE)
   public void youngestFunc_nullResult(CacheContext context,
       @ExpireAfterWrite FixedExpiration<Int, Int> expireAfterWrite) {
+    @SuppressWarnings("NullAway")
     var result = expireAfterWrite.youngest(stream -> null);
     assertThat(result).isNull();
   }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/InternerTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/InternerTest.java
index 662caaa84c..c72e9fad5f 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/InternerTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/InternerTest.java
@@ -65,6 +65,7 @@ public static TestSuite suite() {
         .createTestSuite();
   }
 
+  @SuppressWarnings("NullAway")
   @Test(dataProvider = "interners")
   public void intern_null(Interner<Int> interner) {
     assertThrows(NullPointerException.class, () -> interner.intern(null));
@@ -143,6 +144,7 @@ public void nullPointerExceptions() {
   }
 
   @Test
+  @SuppressWarnings("NullAway")
   public void factory() {
     assertThat(Interned.FACTORY.newReferenceKey(new Object(), null))
         .isInstanceOf(WeakKeyEqualsReference.class);
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LinkedDequeSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LinkedDequeSubject.java
index 209b281e48..f1766c5e76 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LinkedDequeSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LinkedDequeSubject.java
@@ -16,9 +16,12 @@
 package com.github.benmanes.caffeine.cache;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Iterator;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.testing.CollectionSubject;
 import com.google.common.collect.Sets;
 import com.google.common.truth.FailureMetadata;
@@ -32,9 +35,10 @@ final class LinkedDequeSubject extends CollectionSubject {
   private final LinkedDeque<Object> actual;
 
   @SuppressWarnings("unchecked")
-  private LinkedDequeSubject(FailureMetadata metadata, LinkedDeque<?> subject) {
+  private LinkedDequeSubject(FailureMetadata metadata, @Nullable LinkedDeque<?> subject) {
     super(metadata, subject);
-    this.actual = (LinkedDeque<Object>) subject;
+    this.actual = requireNonNull((LinkedDeque<Object>) subject);
+
   }
 
   public static Factory<LinkedDequeSubject, LinkedDeque<?>> deque() {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LocalCacheSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LocalCacheSubject.java
index e4163ad913..13890f5654 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LocalCacheSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/LocalCacheSubject.java
@@ -19,6 +19,7 @@
 import static com.github.benmanes.caffeine.testing.Awaits.await;
 import static com.github.benmanes.caffeine.testing.MapSubject.map;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Collection;
 import java.util.Map;
@@ -26,6 +27,8 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.Async.AsyncWeigher;
 import com.github.benmanes.caffeine.cache.BoundedLocalCache.BoundedLocalAsyncCache;
 import com.github.benmanes.caffeine.cache.BoundedLocalCache.BoundedLocalAsyncLoadingCache;
@@ -38,7 +41,7 @@
 import com.github.benmanes.caffeine.cache.UnboundedLocalCache.UnboundedLocalAsyncLoadingCache;
 import com.github.benmanes.caffeine.cache.UnboundedLocalCache.UnboundedLocalManualCache;
 import com.github.benmanes.caffeine.cache.stats.StatsCounter;
-import com.github.benmanes.caffeine.cache.testing.Weighers;
+import com.github.benmanes.caffeine.cache.testing.Weighers.SkippedWeigher;
 import com.google.common.collect.ImmutableTable;
 import com.google.common.collect.Sets;
 import com.google.common.truth.FailureMetadata;
@@ -54,9 +57,9 @@
 public final class LocalCacheSubject extends Subject {
   private final Object actual;
 
-  private LocalCacheSubject(FailureMetadata metadata, Object subject) {
+  private LocalCacheSubject(FailureMetadata metadata, @Nullable Object subject) {
     super(metadata, subject);
-    this.actual = subject;
+    this.actual = requireNonNull(subject);
   }
 
   public static Factory<LocalCacheSubject, AsyncCache<?, ?>> asyncLocal() {
@@ -298,11 +301,12 @@ private void checkLinks(BoundedLocalCache<Object, Object> bounded,
     long totalWeightedSize = 0;
     Set<Node<Object, Object>> seen = Sets.newIdentityHashSet();
     for (var cell : deques.cellSet()) {
-      long weightedSize = scanLinks(bounded, cell.getValue(), seen);
-      check("%s: %s in %s", cell.getRowKey(), cell.getValue(), bounded.data)
+      var deque = requireNonNull(cell.getValue());
+      long weightedSize = scanLinks(bounded, deque, seen);
+      check("%s: %s in %s", cell.getRowKey(), deque, bounded.data)
           .that(weightedSize).isEqualTo(cell.getColumnKey());
-      totalSize += cell.getValue().size();
       totalWeightedSize += weightedSize;
+      totalSize += deque.size();
     }
     check("linkSize").withMessage("cache.size() != links").that(bounded).hasSize(seen.size());
     check("totalSize").withMessage("cache.size() == deque.size()").that(bounded).hasSize(totalSize);
@@ -354,7 +358,7 @@ private void checkNode(BoundedLocalCache<Object, Object> bounded, Node<Object, O
   }
 
   private void checkKey(BoundedLocalCache<Object, Object> bounded,
-      Node<Object, Object> node, Object key, Object value) {
+      Node<Object, Object> node, @Nullable Object key, @Nullable Object value) {
     if (bounded.collectKeys()) {
       if ((key != null) && (value != null)) {
         check("bounded").that(bounded).containsKey(key);
@@ -368,10 +372,11 @@ private void checkKey(BoundedLocalCache<Object, Object> bounded,
   }
 
   private void checkValue(BoundedLocalCache<Object, Object> bounded,
-      Node<Object, Object> node, Object key, Object value) {
+      Node<Object, Object> node, @Nullable Object key, @Nullable Object value) {
     if (!bounded.collectValues()) {
       check("value").that(value).isNotNull();
       if ((key != null) && !bounded.hasExpired(node, bounded.expirationTicker().read())) {
+        requireNonNull(value);
         check("containsValue(value) for key %s", key)
             .about(map()).that(bounded).containsValue(value);
       }
@@ -379,7 +384,7 @@ private void checkValue(BoundedLocalCache<Object, Object> bounded,
     checkIfAsyncValue(value);
   }
 
-  private void checkIfAsyncValue(Object value) {
+  private void checkIfAsyncValue(@Nullable Object value) {
     if (value instanceof CompletableFuture<?>) {
       var future = (CompletableFuture<?>) value;
       if (!future.isDone() || future.isCompletedExceptionally()) {
@@ -390,18 +395,22 @@ private void checkIfAsyncValue(Object value) {
   }
 
   private void checkWeight(BoundedLocalCache<Object, Object> bounded,
-      Node<Object, Object> node, Object key, Object value) {
+      Node<Object, Object> node, @Nullable Object key, @Nullable Object value) {
     check("node.getWeight").that(node.getWeight()).isAtLeast(0);
+    if ((key == null) || (value == null)) {
+      return;
+    }
 
-    var weigher = bounded.weigher;
-    boolean canCheckWeight = (weigher == Weighers.random());
+    Weigher<?, ?> weigher = bounded.weigher;
     if (weigher instanceof AsyncWeigher) {
-      @SuppressWarnings("rawtypes")
-      var asyncWeigher = (AsyncWeigher) weigher;
-      canCheckWeight = (asyncWeigher.delegate == Weighers.random());
+      weigher = ((AsyncWeigher<?, ?>) weigher).delegate;
+    }
+    if (weigher instanceof BoundedWeigher) {
+      weigher = ((BoundedWeigher<?, ?>) weigher).delegate;
     }
-    if (canCheckWeight) {
-      check("node.getWeight()").that(node.getWeight()).isEqualTo(weigher.weigh(key, value));
+    if (!(weigher instanceof SkippedWeigher)) {
+      int weight = bounded.weigher.weigh(key, value);
+      check("node.getWeight()").that(node.getWeight()).isEqualTo(weight);
     }
   }
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/PacerTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/PacerTest.java
index 550f1e0f40..2f0c1f7d06 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/PacerTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/PacerTest.java
@@ -20,6 +20,7 @@
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
+import static org.mockito.quality.Strictness.STRICT_STUBS;
 
 import java.util.Random;
 import java.util.concurrent.CompletableFuture;
@@ -28,8 +29,10 @@
 import java.util.concurrent.TimeUnit;
 
 import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
 import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 import com.google.common.primitives.Ints;
@@ -38,6 +41,8 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 @Test(singleThreaded = true)
+@Listeners(MockitoTestNGListener.class)
+@MockitoSettings(strictness = STRICT_STUBS)
 public final class PacerTest {
   private static final long ONE_MINUTE_IN_NANOS = TimeUnit.MINUTES.toNanos(1);
   private static final Random random = new Random();
@@ -51,8 +56,7 @@ public final class PacerTest {
   Pacer pacer;
 
   @BeforeMethod
-  public void beforeMethod() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
+  public void beforeMethod() {
     pacer = new Pacer(scheduler);
   }
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReferenceTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReferenceTest.java
index 253b11f3c6..cef2647fe9 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReferenceTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReferenceTest.java
@@ -30,6 +30,7 @@
 import static com.google.common.base.Predicates.not;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
@@ -299,7 +300,8 @@ public void invalidateAll_iterable(Cache<Int, Int> cache, CacheContext context)
     List<Map.Entry<Int, Int>> collected;
     var keys = context.firstMiddleLastKeys();
     if (context.isStrongValues()) {
-      retained = Maps.toMap(context.firstMiddleLastKeys(), key -> context.original().get(key));
+      retained = Maps.toMap(context.firstMiddleLastKeys(),
+          key -> requireNonNull(context.original().get(key)));
       collected = getExpectedAfterGc(context,
           Maps.filterKeys(context.original(), not(keys::contains)));
     } else {
@@ -335,7 +337,8 @@ public void invalidateAll_full(Cache<Int, Int> cache, CacheContext context) {
     List<Map.Entry<Int, Int>> collected = getExpectedAfterGc(context,
         Maps.filterKeys(context.original(), not(keys::contains)));
     if (context.isStrongValues()) {
-      retained = Maps.toMap(context.firstMiddleLastKeys(), key -> context.original().get(key));
+      retained = Maps.toMap(context.firstMiddleLastKeys(),
+          key -> requireNonNull(context.original().get(key)));
     } else {
       retained = Map.of();
       for (var key : keys) {
@@ -589,7 +592,8 @@ public void containsValue(Map<Int, Int> map, CacheContext context) {
       maximumSize = Maximum.DISABLED, weigher = CacheWeigher.DISABLED,
       stats = Stats.ENABLED, removalListener = Listener.CONSUMING)
   public void clear(Map<Int, Int> map, CacheContext context) {
-    var retained = Maps.toMap(context.firstMiddleLastKeys(), key -> context.original().get(key));
+    var retained = Maps.toMap(context.firstMiddleLastKeys(),
+        key -> requireNonNull(context.original().get(key)));
     var collected = getExpectedAfterGc(context, Maps.difference(
         context.original(), retained).entriesOnlyOnLeft());
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/RefreshAfterWriteTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/RefreshAfterWriteTest.java
index 2be25f8e83..efb7a137d9 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/RefreshAfterWriteTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/RefreshAfterWriteTest.java
@@ -30,6 +30,7 @@
 import static com.github.benmanes.caffeine.testing.LoggingEvents.logEvents;
 import static com.github.benmanes.caffeine.testing.MapSubject.assertThat;
 import static com.google.common.truth.Truth.assertThat;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThrows;
@@ -230,7 +231,7 @@ public void refreshIfNeeded_replaced(LoadingCache<Int, Int> cache, CacheContext
     assertThat(value).isNotNull();
 
     assertThat(cache.policy().refreshes()).isNotEmpty();
-    var future = cache.policy().refreshes().get(context.firstKey());
+    var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
 
     cache.put(context.firstKey(), context.absentValue());
     future.complete(context.absentKey().negate());
@@ -256,7 +257,7 @@ public void refreshIfNeeded_expired(LoadingCache<Int, Int> cache, CacheContext c
     assertThat(value).isNotNull();
 
     assertThat(cache.policy().refreshes()).isNotEmpty();
-    var future = cache.policy().refreshes().get(context.firstKey());
+    var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
 
     context.ticker().advance(Duration.ofMinutes(1));
     future.complete(context.absentValue());
@@ -280,7 +281,7 @@ public void refreshIfNeeded_absent_newValue(LoadingCache<Int, Int> cache, CacheC
     assertThat(value).isNotNull();
 
     assertThat(cache.policy().refreshes()).isNotEmpty();
-    var future = cache.policy().refreshes().get(context.firstKey());
+    var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
 
     cache.invalidate(context.firstKey());
     assertThat(cache).doesNotContainKey(context.firstKey());
@@ -306,7 +307,7 @@ public void refreshIfNeeded_absent_nullValue(LoadingCache<Int, Int> cache, Cache
     assertThat(value).isNotNull();
 
     assertThat(cache.policy().refreshes()).isNotEmpty();
-    var future = cache.policy().refreshes().get(context.firstKey());
+    var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
 
     cache.invalidate(context.firstKey());
     future.complete(null);
@@ -404,6 +405,7 @@ public void refreshIfNeeded_nullFuture(CacheContext context) {
       @Override public Int load(Int key) {
         throw new IllegalStateException();
       }
+      @SuppressWarnings("NullAway")
       @Override public CompletableFuture<Int> asyncReload(
           Int key, Int oldValue, Executor executor) {
         refreshed.set(true);
@@ -521,7 +523,8 @@ public void getAllPresent_delayed(LoadingCache<Int, Int> cache, CacheContext con
     if (context.isCaffeine()) {
       var replaced = new HashMap<Int, Int>();
       for (var key : context.firstMiddleLastKeys()) {
-        cache.policy().refreshes().get(key).complete(key);
+        var future = requireNonNull(cache.policy().refreshes().get(key));
+        future.complete(key);
         replaced.put(key, context.original().get(key));
       }
       assertThat(context).removalNotifications().withCause(REPLACED)
@@ -554,7 +557,7 @@ public void getFunc_immediate(LoadingCache<Int, Int> cache, CacheContext context
   @CacheSpec(refreshAfterWrite = Expire.ONE_MINUTE, loader = Loader.ASYNC_INCOMPLETE,
       population = { Population.PARTIAL, Population.FULL })
   public void getFunc_delayed(LoadingCache<Int, Int> cache, CacheContext context) {
-    Function<Int, Int> mappingFunction = context.original()::get;
+    Function<Int, Int> mappingFunction = key -> requireNonNull(context.original().get(key));
     context.ticker().advance(Duration.ofSeconds(30));
     var value = cache.get(context.firstKey(), mappingFunction);
     assertThat(value).isNotNull();
@@ -575,7 +578,7 @@ public void getFunc_delayed(LoadingCache<Int, Int> cache, CacheContext context)
   @CacheSpec(refreshAfterWrite = Expire.ONE_MINUTE,
       population = { Population.PARTIAL, Population.FULL })
   public void getFunc_async(AsyncLoadingCache<Int, Int> cache, CacheContext context) {
-    Function<Int, Int> mappingFunction = context.original()::get;
+    Function<Int, Int> mappingFunction = key -> requireNonNull(context.original().get(key));
     context.ticker().advance(Duration.ofSeconds(30));
     cache.get(context.firstKey(), mappingFunction).join();
     context.ticker().advance(Duration.ofSeconds(45));
@@ -620,7 +623,8 @@ public void get_delayed(LoadingCache<Int, Int> cache, CacheContext context) {
     assertThat(cache.get(context.firstKey())).isEqualTo(context.firstKey().negate());
 
     if (context.isCaffeine()) {
-      cache.policy().refreshes().get(context.firstKey()).complete(context.firstKey());
+      var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
+      future.complete(context.firstKey());
       assertThat(context).removalNotifications().withCause(REPLACED)
           .contains(context.firstKey(), context.original().get(context.firstKey()))
           .exclusively();
@@ -751,7 +755,8 @@ public void getAll_delayed(LoadingCache<Int, Int> cache, CacheContext context) {
 
     if (context.isCaffeine()) {
       for (var key : keys) {
-        cache.policy().refreshes().get(key).complete(key);
+        var future = requireNonNull(cache.policy().refreshes().get(key));
+        future.complete(key);
       }
       assertThat(context).removalNotifications().withCause(REPLACED)
           .contains(Maps.filterKeys(context.original(), context.firstMiddleLastKeys()::contains))
@@ -915,6 +920,7 @@ public void refreshes(LoadingCache<Int, Int> cache, CacheContext context) {
 
     var future = cache.policy().refreshes().get(context.firstKey());
     assertThat(future).isNotNull();
+    requireNonNull(future);
 
     future.complete(Int.MAX_VALUE);
     assertThat(cache.policy().refreshes()).isExhaustivelyEmpty();
@@ -929,7 +935,7 @@ public void refreshes_nullLookup(LoadingCache<Int, Int> cache, CacheContext cont
     var value = cache.getIfPresent(context.firstKey());
     assertThat(value).isNotNull();
 
-    var future = cache.policy().refreshes().get(context.firstKey());
+    var future = requireNonNull(cache.policy().refreshes().get(context.firstKey()));
     assertThat(cache.policy().refreshes().get(null)).isNull();
     assertThat(cache.policy().refreshes().containsKey(null)).isFalse();
     assertThat(cache.policy().refreshes().containsValue(null)).isFalse();
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReserializableSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReserializableSubject.java
index 533d351ef9..46de128f79 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReserializableSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReserializableSubject.java
@@ -17,6 +17,9 @@
 
 import static com.github.benmanes.caffeine.cache.testing.AsyncCacheSubject.asyncCache;
 import static com.github.benmanes.caffeine.cache.testing.CacheSubject.cache;
+import static java.util.Objects.requireNonNull;
+
+import org.jspecify.annotations.Nullable;
 
 import com.github.benmanes.caffeine.cache.Async.AsyncEvictionListener;
 import com.github.benmanes.caffeine.cache.Async.AsyncExpiry;
@@ -39,9 +42,9 @@
 public final class ReserializableSubject extends Subject {
   private final Object actual;
 
-  private ReserializableSubject(FailureMetadata metadata, Object subject) {
+  private ReserializableSubject(FailureMetadata metadata, @Nullable Object subject) {
     super(metadata, subject);
-    this.actual = subject;
+    this.actual = requireNonNull(subject);
   }
 
   public static Factory<ReserializableSubject, AsyncCache<?, ?>> asyncReserializable() {
@@ -257,7 +260,8 @@ private void checkUnboundedLocalCache(
       UnboundedLocalCache<?, ?> original, UnboundedLocalCache<?, ?> copy) {
     check("isRecordingStats").that(copy.isRecordingStats).isEqualTo(original.isRecordingStats);
 
-    if (original.removalListener == null) {
+    if ((original.removalListener == null) || (copy.removalListener == null)) {
+      check("removalListener").that(original.removalListener).isNull();
       check("removalListener").that(copy.removalListener).isNull();
     } else if (copy.removalListener.getClass() != original.removalListener.getClass()) {
       check("removalListener").that(copy.removalListener).isNotNull();
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/SchedulerTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/SchedulerTest.java
index 5864fd7cc3..fd5b09fe90 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/SchedulerTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/SchedulerTest.java
@@ -125,6 +125,7 @@ public void disabledFuture_null() {
   /* --------------- guarded --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void guardedScheduler_null() {
     assertThrows(NullPointerException.class, () -> Scheduler.guardedScheduler(null));
   }
@@ -166,6 +167,7 @@ public void guardedScheduler_exception() {
   /* --------------- ScheduledExecutorService --------------- */
 
   @Test
+  @SuppressWarnings("NullAway")
   public void scheduledExecutorService_null() {
     assertThrows(NullPointerException.class, () -> Scheduler.forScheduledExecutorService(null));
   }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/Stresser.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/Stresser.java
index f617d5d2ca..cb98552170 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/Stresser.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/Stresser.java
@@ -138,7 +138,7 @@ private void status() {
     System.out.printf(US, "Size = %,d (max: %,d)%n",
         local.data.mappingCount(), workload.maxEntries);
     System.out.printf(US, "Lock = [%s%n", StringUtils.substringAfter(evictionLock.toString(), "["));
-    System.out.printf(US, "Pending reloads = %,d%n", local.refreshes.size());
+    System.out.printf(US, "Pending reloads = %,d%n", local.refreshes().size());
     System.out.printf(US, "Pending tasks = %,d%n",
         ForkJoinPool.commonPool().getQueuedSubmissionCount());
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/TimerWheelTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/TimerWheelTest.java
index 4141be2b87..ec2f23b695 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/TimerWheelTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/TimerWheelTest.java
@@ -29,6 +29,7 @@
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
+import static org.mockito.quality.Strictness.LENIENT;
 
 import java.lang.ref.ReferenceQueue;
 import java.time.Duration;
@@ -48,11 +49,13 @@
 import org.mockito.ArgumentCaptor;
 import org.mockito.Captor;
 import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
 import org.testng.ITestResult;
 import org.testng.annotations.AfterMethod;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.DataProvider;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 import com.github.benmanes.caffeine.cache.TimerWheel.Sentinel;
@@ -65,6 +68,8 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 @Test(singleThreaded = true)
+@MockitoSettings(strictness = LENIENT)
+@Listeners(MockitoTestNGListener.class)
 @SuppressWarnings({"ClassEscapesDefinedScope", "GuardedBy"})
 public final class TimerWheelTest {
   private static final Random random = new Random();
@@ -76,9 +81,8 @@ public final class TimerWheelTest {
   TimerWheel<Long, Long> timerWheel;
 
   @BeforeMethod
-  public void beforeMethod() throws Exception {
+  public void beforeMethod() {
     Reset.setThreadLocalRandom(random.nextInt(), random.nextInt());
-    MockitoAnnotations.openMocks(this).close();
     timerWheel = new TimerWheel<>();
   }
 
@@ -203,17 +207,13 @@ public void advance_exception() {
 
   @Test(dataProvider = "clock")
   public void getExpirationDelay_empty(long clock) {
-    when(cache.evictEntry(any(), any(), anyLong())).thenReturn(true);
     timerWheel.nanos = clock;
-
     assertThat(timerWheel.getExpirationDelay()).isEqualTo(Long.MAX_VALUE);
   }
 
   @Test(dataProvider = "clock")
   public void getExpirationDelay_firstWheel(long clock) {
-    when(cache.evictEntry(any(), any(), anyLong())).thenReturn(true);
     timerWheel.nanos = clock;
-
     long delay = Duration.ofSeconds(1).toNanos();
     timerWheel.schedule(new Timer(clock + delay));
     assertThat(timerWheel.getExpirationDelay()).isAtMost(SPANS[0]);
@@ -221,9 +221,7 @@ public void getExpirationDelay_firstWheel(long clock) {
 
   @Test(dataProvider = "clock")
   public void getExpirationDelay_lastWheel(long clock) {
-    when(cache.evictEntry(any(), any(), anyLong())).thenReturn(true);
     timerWheel.nanos = clock;
-
     long delay = Duration.ofDays(14).toNanos();
     timerWheel.schedule(new Timer(clock + delay));
     assertThat(timerWheel.getExpirationDelay()).isAtMost(delay);
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/AsyncCacheSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/AsyncCacheSubject.java
index 02d56c2bb0..d2adb0dd9b 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/AsyncCacheSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/AsyncCacheSubject.java
@@ -20,10 +20,13 @@
 import static com.github.benmanes.caffeine.cache.testing.CacheSubject.cache;
 import static com.github.benmanes.caffeine.testing.MapSubject.map;
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Map;
 import java.util.concurrent.Future;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.AsyncCache;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
@@ -36,9 +39,9 @@
 public final class AsyncCacheSubject extends Subject {
   private final AsyncCache<?, ?> actual;
 
-  private AsyncCacheSubject(FailureMetadata metadata, AsyncCache<?, ?> subject) {
+  private AsyncCacheSubject(FailureMetadata metadata, @Nullable AsyncCache<?, ?> subject) {
     super(metadata, subject);
-    this.actual = subject;
+    this.actual = requireNonNull(subject);
   }
 
   public static Factory<AsyncCacheSubject, AsyncCache<?, ?>> asyncCache() {
@@ -81,7 +84,7 @@ public void doesNotContainKey(Object key) {
   }
 
   /** Fails if the cache does not contain the given value. */
-  public void containsValue(Object value) {
+  public void containsValue(@Nullable Object value) {
     if (value instanceof Future<?>) {
       check("cache").about(map()).that(actual.asMap()).containsValue(value);
     } else {
@@ -90,7 +93,7 @@ public void containsValue(Object value) {
   }
 
   /** Fails if the cache does not contain the given entry. */
-  public void containsEntry(Object key, Object value) {
+  public void containsEntry(Object key, @Nullable Object value) {
     if (value instanceof Future<?>) {
       check("cache").that(actual.asMap()).containsEntry(key, value);
     } else {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContext.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContext.java
index 016c317c0b..26a0d8d8eb 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContext.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContext.java
@@ -30,6 +30,7 @@
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.function.Function;
 
+import org.jspecify.annotations.NullUnmarked;
 import org.jspecify.annotations.Nullable;
 
 import com.github.benmanes.caffeine.cache.AsyncCache;
@@ -92,7 +93,6 @@ public final class CacheContext {
   final TrackingExecutor executor;
   final ReferenceType keyStrength;
   final CacheWeigher cacheWeigher;
-  final Expiry<Int, Int> expiry;
   final Map<Int, Int> original;
   final CacheExpiry expiryType;
   final Population population;
@@ -106,6 +106,8 @@ public final class CacheContext {
   final Loader loader;
   final Stats stats;
 
+  final @Nullable Expiry<Int, Int> expiry;
+
   final boolean isAsyncLoader;
 
   CacheBuilder<Object, Object> guava;
@@ -124,7 +126,7 @@ public final class CacheContext {
 
   @Nullable Map<Int, Int> absent;
 
-  @SuppressWarnings({"PMD.ExcessiveParameterList", "TooManyParameters"})
+  @SuppressWarnings({"NullAway.Init", "PMD.ExcessiveParameterList", "TooManyParameters"})
   public CacheContext(InitialCapacity initialCapacity, Stats stats, CacheWeigher cacheWeigher,
       Maximum maximumSize, CacheExpiry expiryType, Expire afterAccess, Expire afterWrite,
       Expire refresh, ReferenceType keyStrength, ReferenceType valueStrength,
@@ -159,7 +161,7 @@ public CacheContext(InitialCapacity initialCapacity, Stats stats, CacheWeigher c
     this.compute = compute;
     this.expiryType = expiryType;
     this.expiryTime = cacheSpec.expiryTime();
-    this.expiry = expiryType.createExpiry(expiryTime);
+    this.expiry = (expiryType == CacheExpiry.DISABLED) ? null : expiryType.createExpiry(expiryTime);
   }
 
   /** Returns a thread local interner for explicit caching. */
@@ -214,16 +216,19 @@ public Population population() {
 
   public Int firstKey() {
     assertWithMessage("Invalid usage of context").that(firstKey).isNotNull();
+    requireNonNull(firstKey);
     return firstKey;
   }
 
   public Int middleKey() {
     assertWithMessage("Invalid usage of context").that(middleKey).isNotNull();
+    requireNonNull(middleKey);
     return middleKey;
   }
 
   public Int lastKey() {
     assertWithMessage("Invalid usage of context").that(lastKey).isNotNull();
+    requireNonNull(lastKey);
     return lastKey;
   }
 
@@ -417,6 +422,7 @@ public boolean expiresVariably() {
     return (expiryType != CacheExpiry.DISABLED);
   }
 
+  @NullUnmarked
   public Expiry<Int, Int> expiry() {
     return expiry;
   }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContextSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContextSubject.java
index a61b262db9..099e1646f3 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContextSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheContextSubject.java
@@ -39,6 +39,8 @@
 import java.util.function.Function;
 import java.util.function.ToLongFunction;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Policy.CacheEntry;
 import com.github.benmanes.caffeine.cache.RemovalCause;
@@ -65,9 +67,9 @@
 public final class CacheContextSubject extends Subject {
   private final CacheContext actual;
 
-  CacheContextSubject(FailureMetadata metadata, CacheContext subject) {
+  CacheContextSubject(FailureMetadata metadata, @Nullable CacheContext subject) {
     super(metadata, subject);
-    this.actual = subject;
+    this.actual = requireNonNull(subject);
   }
 
   public static Factory<CacheContextSubject, CacheContext> context() {
@@ -212,9 +214,9 @@ public static final class StatsSubject extends Subject {
     private final CacheContext actual;
     private final boolean isDirect;
 
-    private StatsSubject(FailureMetadata metadata, CacheContext context) {
+    private StatsSubject(FailureMetadata metadata, @Nullable CacheContext context) {
       super(metadata, context);
-      this.actual = context;
+      this.actual = requireNonNull(context);
       this.isDirect = !context.isRecordingStats()
           || (context.executorType() == CacheExecutor.DIRECT);
     }
@@ -290,6 +292,7 @@ private ListenerSubject(FailureMetadata metadata, CacheContext context,
     private static Factory<ListenerSubject, CacheContext> factoryOf(
         RemovalListenerType... removalListenerTypes) {
       return (metadata, context) -> {
+        requireNonNull(context);
         var subject = Arrays.stream(removalListenerTypes)
             .filter(listener -> listener.isConsumingListener(context))
             .collect(toImmutableMap(identity(), listener -> listener.instance(context)));
@@ -356,7 +359,7 @@ private WithCause(RemovalCause cause) {
       }
 
       @CanIgnoreReturnValue
-      public Exclusive contains(Int key, Int value) {
+      public Exclusive contains(Int key, @Nullable Int value) {
         return contains(new SimpleEntry<>(key, value));
       }
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSpec.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSpec.java
index 69f6cfa86c..d1d5c7e96d 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSpec.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSpec.java
@@ -54,6 +54,7 @@
 import com.github.benmanes.caffeine.cache.Scheduler;
 import com.github.benmanes.caffeine.cache.Weigher;
 import com.github.benmanes.caffeine.cache.testing.RemovalListeners.ConsumingRemovalListener;
+import com.github.benmanes.caffeine.cache.testing.Weighers.SkippedWeigher;
 import com.github.benmanes.caffeine.testing.ConcurrentTestHarness;
 import com.github.benmanes.caffeine.testing.Int;
 import com.google.common.collect.Maps;
@@ -198,12 +199,18 @@ enum CacheWeigher {
     VALUE(() -> (key, value) -> Math.abs(((Int) value).intValue())),
     /** A flag indicating that the entry is weighted by the value's collection size. */
     COLLECTION(() -> (key, value) -> ((Collection<?>) value).size()),
-    /** A flag indicating that the entry's weight is randomly changing. */
+    /**
+     * A flag indicating that the entry's weight is randomly changing and is skipped by automatic
+     * validation checks.
+     */
     RANDOM(Weighers::random),
-    /** A flag indicating that the entry's weight records interactions. */
+    /**
+     * A flag indicating that the entry's weight records interactions and is skipped by automatic
+     * automatic validation checks.
+     */
     @SuppressWarnings("unchecked")
     MOCKITO(() -> {
-      Weigher<Object, Object> weigher = Mockito.mock();
+      SkippedWeigher<Object, Object> weigher = Mockito.mock();
       when(weigher.weigh(any(), any())).thenReturn(1);
       return weigher;
     });
@@ -267,7 +274,7 @@ CacheExpiry[] expiry() default {
   enum CacheExpiry {
     DISABLED {
       @Override public <K, V> Expiry<K, V> createExpiry(Expire expiryTime) {
-        return null;
+        throw new AssertionError();
       }
     },
     MOCKITO {
@@ -419,6 +426,7 @@ enum Loader implements CacheLoader<Int, Int> {
     },
     /** A loader that always returns null (no mapping). */
     NULL {
+      @SuppressWarnings("NullAway")
       @Override public Int load(Int key) {
         return null;
       }
@@ -461,7 +469,9 @@ enum Loader implements CacheLoader<Int, Int> {
       @Override public Int load(Int key) {
         throw new UnsupportedOperationException();
       }
-      @SuppressWarnings({"PMD.ReturnEmptyCollectionRatherThanNull", "ReturnsNullCollection"})
+
+      @SuppressWarnings({"NullAway",
+        "PMD.ReturnEmptyCollectionRatherThanNull", "ReturnsNullCollection"})
       @Override public Map<Int, Int> loadAll(Set<? extends Int> keys) {
         return null;
       }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSubject.java
index 726e299940..c37db5ff51 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/CacheSubject.java
@@ -21,10 +21,13 @@
 import static com.github.benmanes.caffeine.testing.MapSubject.map;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Map;
 import java.util.Objects;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.Cache;
 import com.google.common.testing.GcFinalization;
 import com.google.common.truth.Correspondence;
@@ -44,9 +47,9 @@ public final class CacheSubject extends Subject {
 
   private final Cache<?, ?> actual;
 
-  CacheSubject(FailureMetadata metadata, Cache<?, ?> subject) {
+  CacheSubject(FailureMetadata metadata, @Nullable Cache<?, ?> subject) {
     super(metadata, subject);
-    this.actual = subject;
+    this.actual = requireNonNull(subject);
   }
 
   public static Factory<CacheSubject, Cache<?, ?>> cache() {
@@ -104,7 +107,7 @@ public void doesNotContainKey(Object key) {
   }
 
   /** Fails if the cache does not contain the given value. */
-  public void containsValue(Object value) {
+  public void containsValue(@Nullable Object value) {
     check("cache").about(map()).that(actual.asMap()).containsValue(value);
   }
 
@@ -114,14 +117,16 @@ public void doesNotContainValue(Object value) {
   }
 
   /** Fails if the cache does not contain the given entry. */
-  public void containsEntry(Object key, Object value) {
+  public void containsEntry(Object key, @Nullable Object value) {
+    requireNonNull(value);
     check("cache").that(actual.asMap())
         .comparingValuesUsing(EQUALITY)
         .containsEntry(key, value);
   }
 
   /** Fails if the cache contains the given entry. */
-  public void doesNotContainEntry(Object key, Object value) {
+  public void doesNotContainEntry(Object key, @Nullable Object value) {
+    requireNonNull(value);
     check("cache").that(actual.asMap())
         .comparingValuesUsing(EQUALITY)
         .doesNotContainEntry(key, value);
@@ -162,8 +167,8 @@ public static final class CleanUpSubject extends Subject {
 
     private final Cache<?, ?> actual;
 
-    private CleanUpSubject(FailureMetadata metadata, Cache<?, ?> cache) {
-      super(metadata, cache.asMap());
+    private CleanUpSubject(FailureMetadata metadata, @Nullable Cache<?, ?> cache) {
+      super(metadata, requireNonNull(cache).asMap());
       this.actual = cache;
     }
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/GuavaCacheFromContext.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/GuavaCacheFromContext.java
index 712338ba5e..1a6af68282 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/GuavaCacheFromContext.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/GuavaCacheFromContext.java
@@ -34,6 +34,8 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.LoadingCache;
 import com.github.benmanes.caffeine.cache.Policy;
@@ -138,7 +140,8 @@ public static <K, V> Cache<K, V> newGuavaCache(CacheContext context) {
     return castedCache;
   }
 
-  static class GuavaCache<K, V> implements Cache<K, V>, Serializable {
+  @SuppressWarnings("NullAway")
+  static class GuavaCache<K, V> implements Cache<K, @Nullable V>, Serializable {
     private static final long serialVersionUID = 1L;
 
     private final com.google.common.cache.Cache<K, V> cache;
@@ -146,10 +149,10 @@ static class GuavaCache<K, V> implements Cache<K, V>, Serializable {
     private final boolean canSnapshot;
     private final Ticker ticker;
 
-    transient ConcurrentMap<K, V> mapView;
     transient StatsCounter statsCounter;
-    transient Policy<K, V> policy;
-    transient Set<K> keySet;
+    transient @Nullable ConcurrentMap<K, V> mapView;
+    transient @Nullable Policy<K, V> policy;
+    transient @Nullable Set<K> keySet;
 
     GuavaCache(com.google.common.cache.Cache<K, V> cache, CacheContext context) {
       this.canSnapshot = context.expires() || context.refreshes();
@@ -160,12 +163,12 @@ static class GuavaCache<K, V> implements Cache<K, V>, Serializable {
     }
 
     @Override
-    public V getIfPresent(Object key) {
+    public @Nullable V getIfPresent(Object key) {
       return cache.getIfPresent(key);
     }
 
     @Override
-    public V get(K key, Function<? super K, ? extends V> mappingFunction) {
+    public @Nullable V get(K key, Function<? super K, ? extends V> mappingFunction) {
       requireNonNull(mappingFunction);
       try {
         return cache.get(key, () -> {
@@ -201,7 +204,7 @@ public Map<K, V> getAll(Iterable<? extends K> keys, Function<? super Set<? exten
       keys.forEach(Objects::requireNonNull);
       requireNonNull(mappingFunction);
 
-      Map<K, V> found = getAllPresent(keys);
+      Map<K, @Nullable V> found = getAllPresent(keys);
       Set<K> keysToLoad = Sets.difference(ImmutableSet.copyOf(keys), found.keySet());
       if (keysToLoad.isEmpty()) {
         return found;
@@ -494,6 +497,7 @@ static class GuavaLoadingCache<K, V> extends GuavaCache<K, V> implements Loading
     }
 
     @Override
+    @SuppressWarnings("NullAway")
     public V get(K key) {
       try {
         return cache.get(key);
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/RemovalListeners.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/RemovalListeners.java
index 18a517e025..4f98c8b5a2 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/RemovalListeners.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/RemovalListeners.java
@@ -22,6 +22,8 @@
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.RejectedExecutionException;
 
+import org.jspecify.annotations.Nullable;
+
 import com.github.benmanes.caffeine.cache.RemovalCause;
 import com.github.benmanes.caffeine.cache.RemovalListener;
 
@@ -44,7 +46,7 @@ public static <K, V> RemovalListener<K, V> rejecting() {
     return new RejectingRemovalListener<>();
   }
 
-  private static void validate(Object key, Object value, RemovalCause cause) {
+  private static void validate(@Nullable Object key, @Nullable Object value, RemovalCause cause) {
     if (cause != RemovalCause.COLLECTED) {
       requireNonNull(key);
       requireNonNull(value);
@@ -60,7 +62,7 @@ public static final class RejectingRemovalListener<K, V>
     public int rejected;
 
     @Override
-    public void onRemoval(K key, V value, RemovalCause cause) {
+    public void onRemoval(@Nullable K key, @Nullable V value, RemovalCause cause) {
       validate(key, value, cause);
 
       if (reject) {
@@ -83,7 +85,7 @@ public ConsumingRemovalListener() {
     }
 
     @Override
-    public void onRemoval(K key, V value, RemovalCause cause) {
+    public void onRemoval(@Nullable K key, @Nullable V value, RemovalCause cause) {
       validate(key, value, cause);
       removed.add(new RemovalNotification<>(key, value, cause));
     }
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/Weighers.java b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/Weighers.java
index d1897c0354..b690593398 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/Weighers.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/cache/testing/Weighers.java
@@ -42,6 +42,9 @@ public static <K, V> Weigher<K, V> random() {
     return (Weigher<K, V>) RandomWeigher.INSTANCE;
   }
 
+  /** A marker to instruct the validation to not check the entry's weight for data consistency. */
+  public interface SkippedWeigher<K, V> extends Weigher<K, V> {}
+
   static final class ConstantWeigher<K, V> implements Weigher<K, V>, Serializable {
     private static final long serialVersionUID = 1L;
 
@@ -57,7 +60,7 @@ static final class ConstantWeigher<K, V> implements Weigher<K, V>, Serializable
     }
   }
 
-  enum RandomWeigher implements Weigher<Object, Object> {
+  enum RandomWeigher implements SkippedWeigher<Object, Object> {
     INSTANCE;
 
     @Override public int weigh(Object key, Object value) {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/eclipse/acceptance/ConcurrentHashMapAcceptanceTest.java b/caffeine/src/test/java/com/github/benmanes/caffeine/eclipse/acceptance/ConcurrentHashMapAcceptanceTest.java
index e9addaf1a2..780306989a 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/eclipse/acceptance/ConcurrentHashMapAcceptanceTest.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/eclipse/acceptance/ConcurrentHashMapAcceptanceTest.java
@@ -25,6 +25,7 @@
 import org.eclipse.collections.impl.list.Interval;
 import org.eclipse.collections.impl.parallel.ParallelIterate;
 import org.eclipse.collections.impl.test.Verify;
+import org.jspecify.annotations.NullUnmarked;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
@@ -35,6 +36,7 @@
  *
  * Ported from Eclipse Collections 11.0.
  */
+@NullUnmarked
 @SuppressWarnings("CanIgnoreReturnValueSuggester")
 public abstract class ConcurrentHashMapAcceptanceTest {
   private ExecutorService executor;
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/CollectionSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/CollectionSubject.java
index 8dc625538e..41e3047533 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/CollectionSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/CollectionSubject.java
@@ -17,6 +17,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Collection;
 import java.util.Deque;
@@ -25,6 +26,8 @@
 import java.util.Queue;
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
+
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.IterableSubject;
 
@@ -34,9 +37,9 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 public class CollectionSubject extends IterableSubject {
-  private final Collection<?> actual;
+  private final @Nullable Collection<?> actual;
 
-  public CollectionSubject(FailureMetadata metadata, Collection<?> subject) {
+  public CollectionSubject(FailureMetadata metadata, @Nullable Collection<?> subject) {
     super(metadata, subject);
     this.actual = subject;
   }
@@ -56,6 +59,7 @@ public final void hasSize(long expectedSize) {
 
   /** Fails if the collection does not have less than the given size. */
   public void hasSizeLessThan(long other) {
+    requireNonNull(actual);
     checkArgument(other >= 0, "expectedSize (%s) must be >= 0", other);
     check("size()").that(actual.size()).isLessThan(Math.toIntExact(other));
   }
@@ -83,11 +87,13 @@ public void isExhaustivelyEmpty() {
   }
 
   private void checkIterable() {
+    requireNonNull(actual);
     check("iterator().hasNext()").that(actual.iterator().hasNext()).isFalse();
   }
 
   @SuppressWarnings("CollectionToArray")
   private void checkCollection() {
+    requireNonNull(actual);
     check("size()").that(actual).hasSize(0);
     check("isEmpty()").that(actual).isEmpty();
     check("toArray()").that(actual.toArray()).isEmpty();
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/FutureSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/FutureSubject.java
index d9272f94ed..0c88752773 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/FutureSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/FutureSubject.java
@@ -16,11 +16,14 @@
 package com.github.benmanes.caffeine.testing;
 
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 
+import org.jspecify.annotations.Nullable;
+
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import com.google.common.truth.ThrowableSubject;
@@ -32,9 +35,9 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 public final class FutureSubject extends Subject {
-  private final CompletableFuture<?> actual;
+  private final @Nullable CompletableFuture<?> actual;
 
-  private FutureSubject(FailureMetadata metadata, CompletableFuture<?> subject) {
+  private FutureSubject(FailureMetadata metadata, @Nullable CompletableFuture<?> subject) {
     super(metadata, subject);
     this.actual = subject;
   }
@@ -43,12 +46,13 @@ public static Factory<FutureSubject, CompletableFuture<?>> future() {
     return FutureSubject::new;
   }
 
-  public static FutureSubject assertThat(CompletableFuture<?> actual) {
+  public static FutureSubject assertThat(@Nullable CompletableFuture<?> actual) {
     return assertAbout(future()).that(actual);
   }
 
   /** Fails if the future is not done. */
   public void isDone() {
+    requireNonNull(actual);
     if (!actual.isDone()) {
       failWithActual("expected to be done", actual);
     }
@@ -56,6 +60,7 @@ public void isDone() {
 
   /** Fails if the future is done. */
   public void isNotDone() {
+    requireNonNull(actual);
     if (actual.isDone()) {
       failWithActual("expected to not be done", actual);
     }
@@ -63,6 +68,7 @@ public void isNotDone() {
 
   /** Fails if the future is has not completed exceptionally. */
   public void hasCompletedExceptionally() {
+    requireNonNull(actual);
     if (!actual.isCompletedExceptionally()) {
       failWithActual("expected to be completed exceptionally", actual.join());
     }
@@ -70,6 +76,7 @@ public void hasCompletedExceptionally() {
 
   /** Fails if the future is not successful with the given value. */
   public void succeedsWith(int value) {
+    requireNonNull(actual);
     var result = actual.join();
     if (result instanceof Int) {
       check("future").that(result).isEqualTo(Int.valueOf(value));
@@ -79,18 +86,21 @@ public void succeedsWith(int value) {
   }
 
   /** Fails if the future is not successful with the given value. */
-  public void succeedsWith(Object value) {
+  public void succeedsWith(@Nullable Object value) {
+    requireNonNull(actual);
     check("future").that(actual.join()).isEqualTo(value);
   }
 
   /** Fails if the future is not successful with a null value. */
   public void succeedsWithNull() {
+    requireNonNull(actual);
     check("future").that(actual.join()).isNull();
   }
 
   /** Fails if the future is did not fail with the given join() exception. */
   @CanIgnoreReturnValue
   public ThrowableSubject failsWith(Class<? extends RuntimeException> clazz) {
+    requireNonNull(actual);
     try {
       failWithActual("join", actual.join());
       throw new AssertionError();
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/Int.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/Int.java
index 89da30ee3d..92ecba261e 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/Int.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/Int.java
@@ -16,6 +16,7 @@
 package com.github.benmanes.caffeine.testing;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.Objects.requireNonNull;
 
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -26,6 +27,8 @@
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 
+import org.jspecify.annotations.Nullable;
+
 import com.google.errorprone.annotations.Immutable;
 
 /**
@@ -48,8 +51,8 @@ public final class Int implements Serializable {
   private final int value;
 
   /** Constructs a newly allocated {@code Int} object with the same {@code value}. */
-  public Int(Int value) {
-    this(value.value);
+  public Int(@Nullable Int value) {
+    this(requireNonNull(value).value);
   }
 
   /**
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/IntSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/IntSubject.java
index 9d034d545e..d53e9a0f67 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/IntSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/IntSubject.java
@@ -17,6 +17,8 @@
 
 import static com.google.common.truth.Truth.assertAbout;
 
+import org.jspecify.annotations.Nullable;
+
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 
@@ -27,7 +29,7 @@
  */
 public final class IntSubject extends Subject {
 
-  private IntSubject(FailureMetadata metadata, Int subject) {
+  private IntSubject(FailureMetadata metadata, @Nullable Int subject) {
     super(metadata, subject);
   }
 
@@ -35,7 +37,7 @@ public static Factory<IntSubject, Int> integer() {
     return IntSubject::new;
   }
 
-  public static IntSubject assertThat(Int actual) {
+  public static IntSubject assertThat(@Nullable Int actual) {
     return assertAbout(integer()).that(actual);
   }
 
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/LoggingEvents.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/LoggingEvents.java
index 4b793c3624..cd1b19bcc3 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/LoggingEvents.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/LoggingEvents.java
@@ -25,6 +25,7 @@
 import java.util.Objects;
 import java.util.function.Predicate;
 
+import org.jspecify.annotations.Nullable;
 import org.slf4j.event.Level;
 
 import com.github.valfirst.slf4jtest.LoggingEvent;
@@ -43,7 +44,8 @@ public final class LoggingEvents extends ForwardingList<LoggingEvent> {
   private final List<Predicate<LoggingEvent>> predicates;
   private final ImmutableList<LoggingEvent> events;
 
-  private ImmutableList<LoggingEvent> filteredEvents;
+  private @Nullable ImmutableList<LoggingEvent> filteredEvents;
+
   private boolean exclusive;
 
   private LoggingEvents(Iterable<LoggingEvent> events) {
diff --git a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/MapSubject.java b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/MapSubject.java
index 32c767e4da..edcffa2501 100644
--- a/caffeine/src/test/java/com/github/benmanes/caffeine/testing/MapSubject.java
+++ b/caffeine/src/test/java/com/github/benmanes/caffeine/testing/MapSubject.java
@@ -18,9 +18,12 @@
 import static com.github.benmanes.caffeine.testing.CollectionSubject.collection;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.truth.Truth.assertAbout;
+import static java.util.Objects.requireNonNull;
 
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Range;
 import com.google.common.truth.FailureMetadata;
@@ -34,9 +37,9 @@
  */
 public class MapSubject extends com.google.common.truth.MapSubject {
   @SuppressWarnings("ImmutableMemberCollection")
-  private final Map<?, ?> actual;
+  private final @Nullable Map<?, ?> actual;
 
-  public MapSubject(FailureMetadata metadata, Map<?, ?> subject) {
+  public MapSubject(FailureMetadata metadata, @Nullable Map<?, ?> subject) {
     super(metadata, subject);
     this.actual = subject;
   }
@@ -56,29 +59,34 @@ public final void hasSize(long expectedSize) {
 
   /** Fails if the map does not have less than the given size. */
   public void hasSizeLessThan(long other) {
+    requireNonNull(actual);
     checkArgument(other >= 0, "expectedSize (%s) must be >= 0", other);
     check("size()").that(actual.size()).isLessThan(Math.toIntExact(other));
   }
 
   /** Fails if the map's size is not in {@code range}. */
   public void hasSizeIn(Range<Integer> range) {
+    requireNonNull(actual);
     check("size()").that(actual.size()).isIn(range);
   }
 
   /** Fails if the map does not contain the given keys, where duplicate keys are ignored. */
   @CanIgnoreReturnValue
   public Ordered containsExactlyKeys(Iterable<?> keys) {
+    requireNonNull(actual);
     return check("containsKeys").that(actual.keySet())
         .containsExactlyElementsIn(ImmutableSet.copyOf(keys));
   }
 
   /** Fails if the map does not contain the given value. */
-  public void containsValue(Object value) {
+  public void containsValue(@Nullable Object value) {
+    requireNonNull(actual);
     check("containsValue").that(actual.values()).contains(value);
   }
 
   /** Fails if the map does contain the given value. */
   public void doesNotContainValue(Object value) {
+    requireNonNull(actual);
     check("containsValue").that(actual.values()).doesNotContain(value);
   }
 
@@ -87,6 +95,7 @@ public void doesNotContainValue(Object value) {
    * methods.
    */
   public void isExhaustivelyEmpty() {
+    requireNonNull(actual);
     isEqualTo(Map.of());
     hasSize(0);
     isEmpty();
diff --git a/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml b/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
index 8ccad706c3..85ee0daab6 100644
--- a/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
+++ b/examples/coalescing-bulkloader-reactor/gradle/libs.versions.toml
@@ -1,7 +1,7 @@
 [versions]
 caffeine = "3.1.8"
 junit = "5.11.3"
-reactor = "3.7.0"
+reactor = "3.7.1"
 truth = "1.4.4"
 versions = "0.51.0"
 
diff --git a/examples/coalescing-bulkloader-reactor/gradle/wrapper/gradle-wrapper.properties b/examples/coalescing-bulkloader-reactor/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/coalescing-bulkloader-reactor/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/coalescing-bulkloader-reactor/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/coalescing-bulkloader-reactor/settings.gradle.kts b/examples/coalescing-bulkloader-reactor/settings.gradle.kts
index 149babf6c3..53023a7268 100644
--- a/examples/coalescing-bulkloader-reactor/settings.gradle.kts
+++ b/examples/coalescing-bulkloader-reactor/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/graal-native/gradle/wrapper/gradle-wrapper.properties b/examples/graal-native/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/graal-native/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/graal-native/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/graal-native/settings.gradle.kts b/examples/graal-native/settings.gradle.kts
index a5e4cd278c..1bb26f570f 100644
--- a/examples/graal-native/settings.gradle.kts
+++ b/examples/graal-native/settings.gradle.kts
@@ -5,7 +5,7 @@ pluginManagement {
   }
 }
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/hibernate/gradle/wrapper/gradle-wrapper.properties b/examples/hibernate/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/hibernate/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/hibernate/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/hibernate/settings.gradle.kts b/examples/hibernate/settings.gradle.kts
index 8a0dbec0f9..a6fd48777d 100644
--- a/examples/hibernate/settings.gradle.kts
+++ b/examples/hibernate/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/indexable/gradle/wrapper/gradle-wrapper.properties b/examples/indexable/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/indexable/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/indexable/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/indexable/settings.gradle.kts b/examples/indexable/settings.gradle.kts
index e17d97cef9..58d363260e 100644
--- a/examples/indexable/settings.gradle.kts
+++ b/examples/indexable/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/resilience-failsafe/gradle/wrapper/gradle-wrapper.properties b/examples/resilience-failsafe/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/resilience-failsafe/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/resilience-failsafe/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/resilience-failsafe/settings.gradle.kts b/examples/resilience-failsafe/settings.gradle.kts
index 0ddb809517..090e9af4ed 100644
--- a/examples/resilience-failsafe/settings.gradle.kts
+++ b/examples/resilience-failsafe/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/examples/write-behind-rxjava/gradle/wrapper/gradle-wrapper.properties b/examples/write-behind-rxjava/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/examples/write-behind-rxjava/gradle/wrapper/gradle-wrapper.properties
+++ b/examples/write-behind-rxjava/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/examples/write-behind-rxjava/settings.gradle.kts b/examples/write-behind-rxjava/settings.gradle.kts
index d04c4ad195..c288943379 100644
--- a/examples/write-behind-rxjava/settings.gradle.kts
+++ b/examples/write-behind-rxjava/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index fa913b441d..450e71ecd9 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -7,14 +7,14 @@ bnd = "7.1.0"
 bouncycastle-jdk18on = "1.79"
 cache2k = "2.6.1.Final"
 caffeine = "3.1.8"
-checkstyle = "10.20.2"
+checkstyle = "10.21.0"
 coherence = "24.09"
 commons-collections4 = "4.4"
 commons-compress = "1.27.1"
 commons-io = "2.18.0"
 commons-lang3 = "3.17.0"
 commons-math3 = "3.6.1"
-commons-text = "1.12.0"
+commons-text = "1.13.0"
 concurrentlinkedhashmap = "1.4.2"
 config = "1.4.3"
 coveralls = "2.12.2"
@@ -32,7 +32,7 @@ felix-scr = "2.2.12"
 findsecbugs = "1.13.0"
 flip-tables = "1.1.1"
 forbidden-apis = "3.8"
-google-java-format = "1.25.0"
+google-java-format = "1.25.2"
 guava = "33.3.1-jre"
 guice = "6.0.0"
 h2 = "2.3.232"
@@ -67,8 +67,9 @@ jvm-dependency-conflict-resolution = "2.1.2"
 kotlin = "2.1.0"
 lincheck = "2.34"
 mockito = "5.14.2"
+mockito-testng = "0.5.2"
 nexus-publish = "2.0.0"
-nullaway = "0.12.1"
+nullaway = "0.12.2"
 nullaway-plugin = "2.1.0"
 okhttp-bom = "4.12.0"
 okio-bom = "3.9.1"
@@ -85,7 +86,7 @@ slf4j-test = "3.0.1"
 snakeyaml = "2.3"
 sonarqube = "6.0.1.5171"
 spotbugs = "4.8.6"
-spotbugs-contrib = "7.6.8"
+spotbugs-contrib = "7.6.9"
 spotbugs-plugin = "6.0.26"
 stream = "2.9.8"
 tcache = "2.0.1"
@@ -171,6 +172,7 @@ junit5-vintage = { module = "org.junit.vintage:junit-vintage-engine", version.re
 kotlin-bom = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "kotlin" }
 lincheck = { module = "org.jetbrains.kotlinx:lincheck-jvm", version.ref = "lincheck" }
 mockito = { module = "org.mockito:mockito-core", version.ref = "mockito" }
+mockito-testng = { module = "org.mockito:mockito-testng", version.ref = "mockito-testng" }
 nullaway = { module = "com.uber.nullaway:nullaway", version.ref = "nullaway" }
 okhttp-bom = { module = "com.squareup.okhttp3:okhttp-bom", version.ref = "okhttp-bom" }
 okio-bom = { module = "com.squareup.okio:okio-bom", version.ref = "okio-bom" }
@@ -211,6 +213,7 @@ constraints = ["bcel", "bouncycastle-jdk18on", "commons-compress", "commons-text
 errorprone-support = ["errorprone-support", "errorprone-support-refaster"]
 junit = ["junit4", "junit5"]
 junit-engines = ["junit5-vintage", "junit5-testng"]
+mockito = ["mockito", "mockito-testng"]
 osgi-test-compile = ["pax-exam-junit4"]
 osgi-test-runtime = ["felix-framework", "felix-scr", "osgi-function",
   "osgi-promise", "pax-exam-container-native", "pax-exam-link-mvn", "pax-url-aether"]
diff --git a/gradle/plugins/settings.gradle.kts b/gradle/plugins/settings.gradle.kts
index 613c7e28ec..c8e64b1f28 100644
--- a/gradle/plugins/settings.gradle.kts
+++ b/gradle/plugins/settings.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
   id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
 }
diff --git a/gradle/plugins/src/main/kotlin/lifecycle/testing.caffeine.gradle.kts b/gradle/plugins/src/main/kotlin/lifecycle/testing.caffeine.gradle.kts
index 56f34e130a..addf43db7e 100644
--- a/gradle/plugins/src/main/kotlin/lifecycle/testing.caffeine.gradle.kts
+++ b/gradle/plugins/src/main/kotlin/lifecycle/testing.caffeine.gradle.kts
@@ -1,9 +1,12 @@
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat.FULL
 import org.gradle.api.tasks.testing.logging.TestLogEvent.FAILED
 import org.gradle.api.tasks.testing.logging.TestLogEvent.SKIPPED
+import net.ltgt.gradle.errorprone.errorprone
+import net.ltgt.gradle.nullaway.nullaway
 
 plugins {
   `java-library`
+  id("errorprone.caffeine")
 }
 
 val mockitoAgent: Configuration by configurations.creating
@@ -13,11 +16,11 @@ dependencies {
   testImplementation(libs.guice)
   testImplementation(libs.truth)
   testImplementation(libs.testng)
-  testImplementation(libs.mockito)
   testImplementation(libs.hamcrest)
   testImplementation(libs.awaitility)
   testImplementation(libs.bundles.junit)
   testImplementation(libs.guava.testlib)
+  testImplementation(libs.bundles.mockito)
   testImplementation(libs.bundles.osgi.test.compile)
 
   testImplementation(platform(libs.asm.bom))
@@ -52,3 +55,17 @@ tasks.withType<Test>().configureEach {
     showCauses = true
   }
 }
+
+tasks.named<JavaCompile>("compileTestJava").configure {
+  options.errorprone.nullaway {
+    customInitializerAnnotations.addAll(listOf(
+      "org.testng.annotations.BeforeClass",
+      "org.testng.annotations.BeforeMethod"))
+    externalInitAnnotations.addAll(listOf(
+      "org.mockito.testng.MockitoSettings",
+      "picocli.CommandLine.Command"))
+    excludedFieldAnnotations.addAll(listOf(
+      "jakarta.inject.Inject",
+      "org.mockito.Mock"))
+  }
+}
diff --git a/gradle/plugins/src/main/kotlin/quality/errorprone.caffeine.gradle.kts b/gradle/plugins/src/main/kotlin/quality/errorprone.caffeine.gradle.kts
index 115c71bedc..a71aa47639 100644
--- a/gradle/plugins/src/main/kotlin/quality/errorprone.caffeine.gradle.kts
+++ b/gradle/plugins/src/main/kotlin/quality/errorprone.caffeine.gradle.kts
@@ -66,6 +66,8 @@ tasks.withType<JavaCompile>().configureEach {
       nullaway {
         if (name.contains("Test")) {
           disable()
+        } else {
+          error()
         }
         annotatedPackages.add("com.github.benmanes.caffeine")
         annotatedPackages.add("com.google.common")
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0cdabcd31b..c085078342 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-rc-1-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
diff --git a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventDispatcherTest.java b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventDispatcherTest.java
index d277676bd0..e46a6a687d 100644
--- a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventDispatcherTest.java
+++ b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventDispatcherTest.java
@@ -24,6 +24,7 @@
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
+import static org.mockito.quality.Strictness.STRICT_STUBS;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -45,9 +46,10 @@
 import javax.cache.event.CacheEntryUpdatedListener;
 
 import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
 import org.testng.annotations.AfterTest;
-import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 import com.google.common.collect.Iterables;
@@ -57,6 +59,9 @@
 /**
  * @author ben.manes@gmail.com (Ben Manes)
  */
+@Test(singleThreaded = true)
+@Listeners(MockitoTestNGListener.class)
+@MockitoSettings(strictness = STRICT_STUBS)
 public final class EventDispatcherTest {
   @Mock Cache<Integer, Integer> cache;
   @Mock CacheEntryCreatedListener<Integer, Integer> createdListener;
@@ -69,11 +74,6 @@ public final class EventDispatcherTest {
   CacheEntryEventFilter<Integer, Integer> allowFilter = event -> true;
   CacheEntryEventFilter<Integer, Integer> rejectFilter = event -> false;
 
-  @BeforeMethod
-  public void beforeMethod() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
-  }
-
   @AfterTest
   public void afterTest() {
     executorService.shutdownNow();
diff --git a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeAwareListenerTest.java b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeAwareListenerTest.java
index 55174b595f..bf200bab5d 100644
--- a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeAwareListenerTest.java
+++ b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeAwareListenerTest.java
@@ -19,6 +19,7 @@
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
+import static org.mockito.quality.Strictness.STRICT_STUBS;
 
 import java.io.IOException;
 
@@ -32,23 +33,22 @@
 
 import org.mockito.Mock;
 import org.mockito.Mockito;
-import org.mockito.MockitoAnnotations;
-import org.testng.annotations.BeforeMethod;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
 import org.testng.annotations.DataProvider;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 /**
  * @author ben.manes@gmail.com (Ben Manes)
  */
+@Test(singleThreaded = true)
 @SuppressWarnings("unchecked")
+@Listeners(MockitoTestNGListener.class)
+@MockitoSettings(strictness = STRICT_STUBS)
 public final class EventTypeAwareListenerTest {
   @Mock Cache<Integer, Integer> cache;
 
-  @BeforeMethod
-  public void before() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
-  }
-
   @Test
   public void closed() throws IOException {
     when(cache.isClosed()).thenReturn(true);
diff --git a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeFilterTest.java b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeFilterTest.java
index 1cc67e0504..4a6b6e0a8a 100644
--- a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeFilterTest.java
+++ b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/EventTypeFilterTest.java
@@ -19,7 +19,7 @@
 
 import javax.cache.event.CacheEntryCreatedListener;
 
-import org.testng.annotations.BeforeTest;
+import org.testng.annotations.BeforeClass;
 import org.testng.annotations.Test;
 
 /**
@@ -28,7 +28,7 @@
 public final class EventTypeFilterTest {
   EventTypeFilter<Integer, Integer> filter;
 
-  @BeforeTest
+  @BeforeClass
   public void before() {
     CacheEntryCreatedListener<Integer, Integer> created = events -> {};
     filter = new EventTypeFilter<>(created, event -> true);
diff --git a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEntryEventTest.java b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEntryEventTest.java
index 3112441b48..2063ee9697 100644
--- a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEntryEventTest.java
+++ b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEntryEventTest.java
@@ -17,6 +17,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
+import static org.mockito.quality.Strictness.STRICT_STUBS;
 
 import java.util.Iterator;
 import java.util.Map;
@@ -26,8 +27,10 @@
 import javax.cache.event.EventType;
 
 import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
-import org.testng.annotations.BeforeTest;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 import com.google.common.collect.testing.IteratorFeature;
@@ -36,14 +39,16 @@
 /**
  * @author ben.manes@gmail.com (Ben Manes)
  */
+@Test(singleThreaded = true)
+@Listeners(MockitoTestNGListener.class)
+@MockitoSettings(strictness = STRICT_STUBS)
 public final class JCacheEntryEventTest {
   @Mock Cache<Integer, Integer> cache;
 
   JCacheEntryEvent<Integer, Integer> event;
 
-  @BeforeTest
-  public void before() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
+  @BeforeMethod
+  public void before() {
     event = new JCacheEntryEvent<>(cache, EventType.CREATED,
         1, /* hasOldValue= */ true, 2, 3);
   }
diff --git a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEvictionListenerTest.java b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEvictionListenerTest.java
index 174ddf9c75..44db10fc59 100644
--- a/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEvictionListenerTest.java
+++ b/jcache/src/test/java/com/github/benmanes/caffeine/jcache/event/JCacheEvictionListenerTest.java
@@ -19,6 +19,7 @@
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
+import static org.mockito.quality.Strictness.STRICT_STUBS;
 
 import java.util.Arrays;
 import java.util.Iterator;
@@ -29,9 +30,11 @@
 import javax.cache.event.CacheEntryRemovedListener;
 
 import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
+import org.mockito.testng.MockitoSettings;
+import org.mockito.testng.MockitoTestNGListener;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.DataProvider;
+import org.testng.annotations.Listeners;
 import org.testng.annotations.Test;
 
 import com.github.benmanes.caffeine.cache.RemovalCause;
@@ -41,6 +44,9 @@
 /**
  * @author ben.manes@gmail.com (Ben Manes)
  */
+@Test(singleThreaded = true)
+@Listeners(MockitoTestNGListener.class)
+@MockitoSettings(strictness = STRICT_STUBS)
 public final class JCacheEvictionListenerTest {
   JCacheEvictionListener<Integer, Integer> listener;
   JCacheStatisticsMXBean statistics;
@@ -49,8 +55,7 @@ public final class JCacheEvictionListenerTest {
   @Mock Cache<Integer, Integer> cache;
 
   @BeforeMethod
-  public void before() throws Exception {
-    MockitoAnnotations.openMocks(this).close();
+  public void before() {
     statistics = new JCacheStatisticsMXBean();
     var dispatcher = new EventDispatcher<Integer, Integer>(Runnable::run);
     listener = new JCacheEvictionListener<>(dispatcher, statistics);
diff --git a/settings.gradle.kts b/settings.gradle.kts
index cab1d2d545..451101b3ab 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -2,9 +2,9 @@ pluginManagement {
   includeBuild("gradle/plugins")
 }
 plugins {
-  id("com.gradle.develocity") version "3.18.2"
+  id("com.gradle.develocity") version "3.19"
   id("com.gradle.common-custom-user-data-gradle-plugin") version "2.0.2"
-  id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
+  id("org.gradle.toolchains.foojay-resolver-convention") version "0.9.0"
 }
 
 dependencyResolutionManagement {