Add MutabilityDetector

immutables/pom.xml

@@ -26,6 +26,12 @@
             <version>3.5.2</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mutabilitydetector</groupId>
+            <artifactId>MutabilityDetector</artifactId>
+            <version>0.9.5</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

immutables/src/test/java/com/baeldung/immutable/ImmutablePersonTest.java

@@ -3,6 +3,7 @@ package com.baeldung.immutable;
 import org.junit.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mutabilitydetector.unittesting.MutabilityAssert.assertImmutable;
 
 public class ImmutablePersonTest {
 
@@ -20,5 +21,7 @@ public class ImmutablePersonTest {
 
         assertThat(john.getAge())
           .isEqualTo(42);
+
+        assertImmutable(com.baeldung.immutable.ImmutablePerson.class);
     }
 }