diff --git a/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4HazelcastJetFactory.java b/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4HazelcastJetFactory.java
index 693f36bb2b4cd4d208496dfe804d635311f6eea5..69ccee100f2946237390c8b19ff0f20036237d37 100644
--- a/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4HazelcastJetFactory.java
+++ b/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4HazelcastJetFactory.java
@@ -57,18 +57,8 @@ public class Uc4HazelcastJetFactory {
    * @throws Exception If either no JetInstance or Pipeline is set, a job cannot be startet.
    */
   public void runUc4Job(final String jobName) throws IllegalStateException { // NOPMD
-
-    // Check if a Jet Instance for UC4 is set.
-    if (this.uc4JetInstance == null) {
-      throw new IllegalStateException("Jet Instance is not set! "
-          + "Cannot start a hazelcast jet job for UC4.");
-    }
-
-    // Check if a Pipeline for UC3 is set.
-    if (this.uc4JetPipeline == null) {
-      throw new IllegalStateException(
-          "Hazelcast Pipeline is not set! Cannot start a hazelcast jet job for UC4.");
-    }
+    Objects.requireNonNull(this.uc4JetInstance, "Jet instance is not set.");
+    Objects.requireNonNull(this.uc4JetPipeline, "Jet pipeline is not set.");
 
     // Adds the job name and joins a job to the JetInstance defined in this factory
     final JobConfig jobConfig = new JobConfig()
diff --git a/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineBuilder.java b/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineBuilder.java
index f15633a8f8cd9beef2d235000d5d2827d06730b8..87d10bc5c0fd417082c12c5a1a26bbf9116c8a50 100644
--- a/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineBuilder.java
+++ b/theodolite-benchmarks/uc4-hazelcastjet/src/main/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineBuilder.java
@@ -17,7 +17,6 @@ import com.hazelcast.jet.pipeline.StreamStageWithKey;
 import com.hazelcast.jet.pipeline.WindowDefinition;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -191,20 +190,10 @@ public class Uc4PipelineBuilder {
         .<Set<String>, Entry<String, ValueGroup>>mapUsingIMap(
             SENSOR_PARENT_MAP_NAME,
             (sensorEvent, sensorParentsSet) -> {
-              // Check whether a groupset exists for a key or not
-              if (sensorParentsSet == null) {
-                // No group set exists for this key: return valuegroup with default null group set.
-                final Set<String> nullSet = new HashSet<>();
-                nullSet.add("NULL-GROUPSET");
-                return Util.entry(sensorEvent.getKey(),
-                    new ValueGroup(sensorEvent.getValue(), nullSet));
-              } else {
-                // Group set exists for this key: return valuegroup with the groupset.
-                final ValueGroup valueParentsPair =
-                    new ValueGroup(sensorEvent.getValue(), sensorParentsSet);
-                // Return solution
-                return Util.entry(sensorEvent.getKey(), valueParentsPair);
-              }
+              final ValueGroup valueParentsPair = new ValueGroup(
+                  sensorEvent.getValue(),
+                  sensorParentsSet == null ? Set.of() : sensorParentsSet);
+              return Util.entry(sensorEvent.getKey(), valueParentsPair);
             });
 
     //////////////////////////////////
diff --git a/theodolite-benchmarks/uc4-hazelcastjet/src/test/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineTest.java b/theodolite-benchmarks/uc4-hazelcastjet/src/test/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineTest.java
index 569f06105dbdb2b99c10d89b5f72585fe011fe19..e59f4cabc5acb09943f1f53dcb881dae001ffc26 100644
--- a/theodolite-benchmarks/uc4-hazelcastjet/src/test/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineTest.java
+++ b/theodolite-benchmarks/uc4-hazelcastjet/src/test/java/rocks/theodolite/benchmarks/uc4/hazelcastjet/Uc4PipelineTest.java
@@ -39,7 +39,6 @@ import rocks.theodolite.benchmarks.uc4.hazelcastjet.uc4specifics.ValueGroupSeria
 @Category(SerialTest.class)
 public class Uc4PipelineTest extends JetTestSupport {
 
-  // TEst Machinery
   JetInstance testInstance = null;
   Pipeline testPipeline = null;
   StreamStage<Entry<String, AggregatedActivePowerRecord>> uc4Topology = null;
@@ -55,7 +54,7 @@ public class Uc4PipelineTest extends JetTestSupport {
     final Double testValueInW = 10.0;
     final int testWindowSize = 5000; // As window size is bugged, not necessary.
 
-    // Create mock jet instance with configuration
+    // Create mocked Hazelcast Jet instance with configuration
     final String testClusterName = randomName();
     final JetConfig testJetConfig = new JetConfig();
     testJetConfig.getHazelcastConfig().setClusterName(testClusterName);
@@ -218,7 +217,6 @@ public class Uc4PipelineTest extends JetTestSupport {
 
   @After
   public void after() {
-    System.out.println("Shutting down");
     // Shuts down all running Jet Instances
     Jet.shutdownAll();
   }