diff --git a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/HistoryServiceFlinkJob.java b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/HistoryServiceFlinkJob.java
index 31b840924afa34243fe0e8afafae5ff862e9a61b..18e54ab6e5857a76ccf70384e17241debe7e3b2b 100644
--- a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/HistoryServiceFlinkJob.java
+++ b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/HistoryServiceFlinkJob.java
@@ -155,7 +155,7 @@ public class HistoryServiceFlinkJob {
             final String newKey = keyFactory.getSensorId(tuple.f0);
             final String newValue = tuple.f1.toString();
             final int hourOfDay = tuple.f0.getHourOfDay();
-            LOGGER.info(newKey + "|" + hourOfDay + ": " + newValue);
+            LOGGER.info("{}|{}: {}", newKey, hourOfDay, newValue);
             return new Tuple2<>(newKey, newValue);
           }
         }).name("map")
diff --git a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKey.java b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKey.java
index ae9559b9601be857e7472b85fa3d35eb06311867..c75bc54e023f90ea5d3487c9b7ecca8cefac27b3 100644
--- a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKey.java
+++ b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKey.java
@@ -32,15 +32,19 @@ public class HourOfDayKey {
 
   @Override
   public int hashCode() {
-    return Objects.hash(hourOfDay, sensorId);
+    return Objects.hash(this.hourOfDay, this.sensorId);
   }
 
   @Override
-  public boolean equals(Object obj) {
-    if (obj == this) return true;
-    if (!(obj instanceof HourOfDayKey)) return false;
+  public boolean equals(final Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (!(obj instanceof HourOfDayKey)) {
+      return false;
+    }
     final HourOfDayKey k = (HourOfDayKey) obj;
-    return hourOfDay == k.hourOfDay && sensorId.equals(k.sensorId);
+    return this.hourOfDay == k.hourOfDay && this.sensorId.equals(k.sensorId);
   }
 
   public byte[] toByteArray() {
diff --git a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKeySerde.java b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKeySerde.java
index f214190227b58a61246d6c319f7a5898cdd21319..b5ab5b986cf11782e465e712334649102303e781 100644
--- a/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKeySerde.java
+++ b/theodolite-benchmarks/uc3-application-flink/src/main/java/theodolite/uc3/application/util/HourOfDayKeySerde.java
@@ -4,19 +4,19 @@ import com.esotericsoftware.kryo.Kryo;
 import com.esotericsoftware.kryo.Serializer;
 import com.esotericsoftware.kryo.io.Input;
 import com.esotericsoftware.kryo.io.Output;
+import java.io.Serializable;
 import org.apache.kafka.common.serialization.Serde;
 import titan.ccp.common.kafka.simpleserdes.BufferSerde;
 import titan.ccp.common.kafka.simpleserdes.ReadBuffer;
 import titan.ccp.common.kafka.simpleserdes.SimpleSerdes;
 import titan.ccp.common.kafka.simpleserdes.WriteBuffer;
 
-import java.io.Serializable;
-
 /**
  * {@link BufferSerde} for a {@link HourOfDayKey}. Use the {@link #create()} method to create a new
  * Kafka {@link Serde}.
  */
-public class HourOfDayKeySerde extends Serializer<HourOfDayKey> implements BufferSerde<HourOfDayKey>, Serializable {
+public class HourOfDayKeySerde extends Serializer<HourOfDayKey>
+    implements BufferSerde<HourOfDayKey>, Serializable {
 
   @Override
   public void serialize(final WriteBuffer buffer, final HourOfDayKey data) {
@@ -36,14 +36,14 @@ public class HourOfDayKeySerde extends Serializer<HourOfDayKey> implements Buffe
   }
 
   @Override
-  public void write(Kryo kryo, Output output, HourOfDayKey object) {
-    byte[] data = object.toByteArray();
+  public void write(final Kryo kryo, final Output output, final HourOfDayKey object) {
+    final byte[] data = object.toByteArray();
     output.writeInt(data.length);
     output.writeBytes(data);
   }
 
   @Override
-  public HourOfDayKey read(Kryo kryo, Input input, Class<HourOfDayKey> type) {
+  public HourOfDayKey read(final Kryo kryo, final Input input, final Class<HourOfDayKey> type) {
     final int numBytes = input.readInt();
     return HourOfDayKey.fromByteArray(input.readBytes(numBytes));
   }