Fix sonar issues

Signed-off-by: SirWayne <dennis.melzer@bosch-si.com>

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiArtifactHash.java

@@ -27,6 +27,7 @@ public class DdiArtifactHash {
      * Default constructor.
      */
     public DdiArtifactHash() {
+        // needed for json create
     }
 
     /**

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiChunk.java

@@ -29,7 +29,7 @@ public class DdiChunk {
     private List<DdiArtifact> artifacts;
 
     public DdiChunk() {
-
+        // needed for json create
     }
 
     /**

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiConfig.java

@@ -34,8 +34,11 @@ public class DdiConfig {
         this.polling = polling;
     }
 
+    /**
+     * Constructor.
+     */
     public DdiConfig() {
-
+        // needed for json create.
     }
 
     public DdiPolling getPolling() {

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiControllerBase.java

@@ -37,7 +37,7 @@ public class DdiControllerBase extends ResourceSupport {
     }
 
     public DdiControllerBase() {
-
+        // needed for json create
     }
 
     public DdiConfig getConfig() {

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiDeployment.java

@@ -23,8 +23,11 @@ public class DdiDeployment {
 
     private List<DdiChunk> chunks;
 
+    /**
+     * Constructor.
+     */
     public DdiDeployment() {
-
+        // needed for json create.
     }
 
     /**

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiDeploymentBase.java

@@ -21,10 +21,10 @@ public class DdiDeploymentBase extends ResourceSupport {
 
     @JsonProperty("id")
     @NotNull
-    private String deplyomentId;
+    private final String deplyomentId;
 
     @NotNull
-    private DdiDeployment deployment;
+    private final DdiDeployment deployment;
 
     /**
      * Constructor.
@@ -35,14 +35,10 @@ public class DdiDeploymentBase extends ResourceSupport {
      *            details.
      */
     public DdiDeploymentBase(final String id, final DdiDeployment deployment) {
-        deplyomentId = id;
+        this.deplyomentId = id;
         this.deployment = deployment;
     }
 
-    public DdiDeploymentBase() {
-
-    }
-
     public DdiDeployment getDeployment() {
         return deployment;
     }

hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/json/model/DdiPolling.java

@@ -30,11 +30,15 @@ public class DdiPolling {
      *            between polls
      */
     public DdiPolling(final String sleep) {
-        super();
         this.sleep = sleep;
     }
 
+    /**
+     * Constructor.
+     *
+     */
     public DdiPolling() {
+        // needed for json create
     }
 
     public String getSleep() {