Fix sonar issues and add DMF tests for maintenance window feature (#655)

* Fix sonar issues.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* POM cleanup and more sonar issues fixed.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Remove unneeded JavaDocs.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* More sonar issues.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* More issues.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Adapt maintenance window to naming.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Add DMF tests.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Readibility.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Typos fixed.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

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

@@ -12,6 +12,7 @@ import java.util.Collections;
 import java.util.List;
 
 import javax.validation.constraints.NotNull;
+
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,7 +31,7 @@ public class DdiDeployment {
     @NotNull
     private List<DdiChunk> chunks;
 
-    private MaintenanceWindowStatus maintenanceWindow = null;
+    private MaintenanceWindowStatus maintenanceWindow;
 
     /**
      * Constructor.