Refactor: Code cleaning

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/database/EmbeddedDatabaseHandler.java

@@ -247,7 +247,7 @@ public class EmbeddedDatabaseHandler {
                     }
                 }
             } catch (IOException e) {
-                throw new RuntimeException(e);
+                throw new EmbeddedDatabaseHandlerException(e);
             }
         } catch (SQLException e) {
             logger.error(Localization.getText("DatabaseHandler.unmarshallingFailure"), id);
@@ -285,7 +285,7 @@ public class EmbeddedDatabaseHandler {
                 }
                 return objects;
             } catch (IOException e) {
-                throw new RuntimeException(e);
+                throw new EmbeddedDatabaseHandlerException(e);
             }
         } catch (SQLException e) {
             logger.error(Localization.getText("DatabaseHandler.unmarshallingFailure"), ids);

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/database/FeatureCache.java

@@ -52,7 +52,7 @@ public class FeatureCache implements CityObjectCache{
         DatabaseCacheLoader.Unmarshaller<GmlId, CityObject> single = handler::unmarshallCityObject;
         DatabaseCacheLoader.BatchUnmarshaller<GmlId, CityObject> batch = handler::unmarshallAllIds;
         cache = Caffeine.newBuilder().maximumSize(3000).removalListener((GmlId key, CityObject value, RemovalCause cause) -> {
-            if (value != null && cause.wasEvicted() && isFeatureMarshallable(value)){
+            if (cause.wasEvicted() && isFeatureMarshallable(value)){
                 handler.marshallCityObject(value);
             }
         }).build(new DatabaseCacheLoader<>(single, batch));

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/exceptions/EmbeddedDatabaseHandlerException.java

@@ -15,4 +15,8 @@ public class EmbeddedDatabaseHandlerException extends RuntimeException{
     public EmbeddedDatabaseHandlerException(String message, Throwable cause) {
         super(message, cause);
     }
+
+    public EmbeddedDatabaseHandlerException(Throwable cause){
+        super(cause);
+    }
 }