diff --git a/client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java b/client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java
index fdc117ba5..503419a47 100644
--- a/client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java
+++ b/client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java
@@ -31,6 +31,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicReference;
 import org.fusesource.jansi.Ansi;
 import org.fusesource.jansi.internal.CLibrary;
@@ -235,22 +236,19 @@ public ExecutionResult execute(ClientOutput output, List<String> argv) {
                 return DefaultResult.success(argv);
             }
 
-            Environment.MVND_THREADS.removeCommandLineOption(args);
-            Environment.MVND_THREADS.addCommandLineOption(args, parameters.threads());
+            Optional<String> threads = Optional.ofNullable(Environment.MVND_THREADS.removeCommandLineOption(args));
+            Environment.MVND_THREADS.addCommandLineOption(args, threads.orElseGet(parameters::threads));
 
-            Environment.MVND_BUILDER.removeCommandLineOption(args);
-            Environment.MVND_BUILDER.addCommandLineOption(args, parameters.builder());
+            Optional<String> builder = Optional.ofNullable(Environment.MVND_BUILDER.removeCommandLineOption(args));
+            Environment.MVND_BUILDER.addCommandLineOption(args, builder.orElseGet(parameters::builder));
 
-            final Path settings = parameters.settings();
-            if (settings != null) {
-                Environment.MAVEN_SETTINGS.removeCommandLineOption(args);
-                Environment.MAVEN_SETTINGS.addCommandLineOption(args, settings.toString());
-            }
+            Optional<String> settings = Optional.ofNullable(Environment.MAVEN_SETTINGS.removeCommandLineOption(args))
+                    .or(() -> Optional.ofNullable(parameters.settings()).map(Path::toString));
+            settings.ifPresent(s -> Environment.MAVEN_SETTINGS.addCommandLineOption(args, s));
 
-            final Path localMavenRepository = parameters.mavenRepoLocal();
-            if (localMavenRepository != null && !Environment.MAVEN_REPO_LOCAL.hasCommandLineOption(args)) {
-                Environment.MAVEN_REPO_LOCAL.addCommandLineOption(args, localMavenRepository.toString());
-            }
+            Optional<String> repo = Optional.ofNullable(Environment.MAVEN_REPO_LOCAL.removeCommandLineOption(args))
+                    .or(() -> Optional.ofNullable(parameters.mavenRepoLocal()).map(Path::toString));
+            repo.ifPresent(r -> Environment.MAVEN_REPO_LOCAL.addCommandLineOption(args, r));
 
             Environment.MVND_TERMINAL_WIDTH.addCommandLineOption(args, Integer.toString(output.getTerminalWidth()));
 
diff --git a/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionNativeIT.java b/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionNativeIT.java
new file mode 100644
index 000000000..f56c95790
--- /dev/null
+++ b/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionNativeIT.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2019-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mvndaemon.mvnd.it;
+
+import java.io.IOException;
+import javax.inject.Inject;
+import org.junit.jupiter.api.Test;
+import org.mvndaemon.mvnd.assertj.TestClientOutput;
+import org.mvndaemon.mvnd.client.Client;
+import org.mvndaemon.mvnd.client.DaemonParameters;
+import org.mvndaemon.mvnd.junit.MvndNativeTest;
+
+@MvndNativeTest(projectDir = "src/test/projects/multi-module")
+public class ThreadOptionNativeIT {
+
+    @Inject
+    Client client;
+
+    @Inject
+    DaemonParameters parameters;
+
+    @Test
+    void minusTSpace2() throws IOException, InterruptedException {
+        final TestClientOutput output = new TestClientOutput();
+
+        client.execute(output, "-T", "2", "verify").assertSuccess();
+
+        output.assertContainsMatchingSubsequence("Using the SmartBuilder implementation with a thread count of 2");
+    }
+
+    @Test
+    void minusT2() throws IOException, InterruptedException {
+        final TestClientOutput output = new TestClientOutput();
+
+        client.execute(output, "-T2", "verify").assertSuccess();
+
+        output.assertContainsMatchingSubsequence("Using the SmartBuilder implementation with a thread count of 2");
+    }
+
+    @Test
+    void minusThreadsSpace2() throws IOException, InterruptedException {
+        final TestClientOutput output = new TestClientOutput();
+
+        client.execute(output, "--threads", "2", "verify").assertSuccess();
+
+        output.assertContainsMatchingSubsequence("Using the SmartBuilder implementation with a thread count of 2");
+    }
+
+    @Test
+    void minusThreads2() throws IOException, InterruptedException {
+        final TestClientOutput output = new TestClientOutput();
+
+        client.execute(output, "--threads=2", "verify").assertSuccess();
+
+        output.assertContainsMatchingSubsequence("Using the SmartBuilder implementation with a thread count of 2");
+    }
+
+    @Test
+    void mvndThreads() throws IOException, InterruptedException {
+        final TestClientOutput output = new TestClientOutput();
+
+        client.execute(output, "-Dmvnd.threads=2", "verify").assertSuccess();
+
+        output.assertContainsMatchingSubsequence("Using the SmartBuilder implementation with a thread count of 2");
+    }
+
+    protected boolean isNative() {
+        return true;
+    }
+}
diff --git a/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionTest.java b/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionTest.java
new file mode 100644
index 000000000..1e4920718
--- /dev/null
+++ b/integration-tests/src/test/java/org/mvndaemon/mvnd/it/ThreadOptionTest.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2019-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mvndaemon.mvnd.it;
+
+import org.mvndaemon.mvnd.junit.MvndTest;
+
+@MvndTest(projectDir = "src/test/projects/multi-module")
+public class ThreadOptionTest extends ThreadOptionNativeIT {
+
+    protected boolean isNative() {
+        return false;
+    }
+}