diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 0e9471247f..12354c1533 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -23,11 +23,11 @@ dependency-check = "10.0.4"
 eclipse-collections = "12.0.0.M3"
 ehcache3 = "3.10.8"
 errorprone = "2.34.0"
-errorprone-plugin = "4.0.1"
+errorprone-plugin = "4.1.0"
 errorprone-support = "0.18.0"
 expiring-map = "0.5.11"
 fast-filter = "1.0.2"
-fastutil = "8.5.14"
+fastutil = "8.5.15"
 felix-framework = "7.0.5"
 felix-scr = "2.2.12"
 findsecbugs = "1.13.0"
@@ -69,7 +69,7 @@ lincheck = "2.34"
 mockito = "5.14.2"
 nexus-publish = "2.0.0"
 nullaway = "0.12.0"
-nullaway-plugin = "2.0.0"
+nullaway-plugin = "2.1.0"
 okhttp-bom = "4.12.0"
 okio-bom = "3.9.1"
 osgi-annotations = "1.5.1"
diff --git a/jcache/build.gradle.kts b/jcache/build.gradle.kts
index 667b93625f..fd9433019d 100644
--- a/jcache/build.gradle.kts
+++ b/jcache/build.gradle.kts
@@ -102,7 +102,7 @@ tasks.named<Javadoc>("javadoc").configure {
 tasks.withType<Test>().configureEach {
   useJUnitPlatform()
   dependsOn(unzipTestKit)
-  testClassesDirs += layout.buildDirectory.files("tck")
+  testClassesDirs = files(testClassesDirs, layout.buildDirectory.files("tck"))
 
   project(":caffeine").plugins.withId("java-library") {
     val caffeineJar = project(":caffeine").tasks.named<Jar>("jar")