diff --git a/src/main/java/edu/hm/hafner/util/FilteredLog.java b/src/main/java/edu/hm/hafner/util/FilteredLog.java
index bde73021..6dece00b 100644
--- a/src/main/java/edu/hm/hafner/util/FilteredLog.java
+++ b/src/main/java/edu/hm/hafner/util/FilteredLog.java
@@ -19,7 +19,7 @@
  *
  * @author Ullrich Hafner
  */
-public final class FilteredLog implements Serializable {
+public class FilteredLog implements Serializable {
     private static final long serialVersionUID = -8552323621953159904L;
 
     private static final int DEFAULT_MAX_LINES = 20;
diff --git a/src/test/java/edu/hm/hafner/util/FilteredLogTest.java b/src/test/java/edu/hm/hafner/util/FilteredLogTest.java
index 1e9feb9c..3bcfb423 100644
--- a/src/test/java/edu/hm/hafner/util/FilteredLogTest.java
+++ b/src/test/java/edu/hm/hafner/util/FilteredLogTest.java
@@ -132,6 +132,7 @@ void shouldAdhereToEquals() {
                 .withIgnoredFields("lock")
                 .withPrefabValues(ReentrantLock.class, new ReentrantLock(), new ReentrantLock())
                 .suppress(Warning.NONFINAL_FIELDS)
+                .suppress(Warning.STRICT_INHERITANCE)
                 .verify();
     }