diff --git a/model/src/main/java/lcsb/mapviewer/model/map/AnnotatedObject.java b/model/src/main/java/lcsb/mapviewer/model/map/AnnotatedObject.java
index cca3829b5240cd05fd511edf93cd51c514cc603c..2a9ec585d0e782d016f3e629837005049d058213 100644
--- a/model/src/main/java/lcsb/mapviewer/model/map/AnnotatedObject.java
+++ b/model/src/main/java/lcsb/mapviewer/model/map/AnnotatedObject.java
@@ -125,6 +125,11 @@ public interface AnnotatedObject extends Serializable {
 	 */
 	void setName(String name);
 
+	/**
+	 * Returns database identifier of the object.
+	 * 
+	 * @return database identifier of the object
+	 */
 	int getId();
 
 	/**
@@ -134,7 +139,18 @@ public interface AnnotatedObject extends Serializable {
 	 */
 	String getStringType();
 
+	/**
+	 * Sets semantic zoom level visibility.
+	 * 
+	 * @param zoomLevelVisibility
+	 *          semantic zoom level visibility
+	 */
 	void setSemanticZoomLevelVisibility(String zoomLevelVisibility);
 
+	/**
+	 * Returns semantic zoom level visibility.
+	 * 
+	 * @return semantic zoom level visibility
+	 */
 	String getSemanticZoomLevelVisibility();
 }
diff --git a/model/src/main/java/lcsb/mapviewer/model/map/compartment/OvalCompartment.java b/model/src/main/java/lcsb/mapviewer/model/map/compartment/OvalCompartment.java
index be5a84f3f9c1349ebe938d52cf86d0de5402f740..3dbbeab40d75cdde78a7c11d1c4e4ed5b54a397d 100644
--- a/model/src/main/java/lcsb/mapviewer/model/map/compartment/OvalCompartment.java
+++ b/model/src/main/java/lcsb/mapviewer/model/map/compartment/OvalCompartment.java
@@ -38,6 +38,12 @@ public class OvalCompartment extends Compartment {
 		super(original);
 	}
 
+	/**
+	 * Default constructor.
+	 * 
+	 * @param elementId
+	 *          identifier of the compartment
+	 */
 	public OvalCompartment(String elementId) {
 		super();
 		setElementId(elementId);
diff --git a/model/src/main/java/lcsb/mapviewer/model/map/species/Element.java b/model/src/main/java/lcsb/mapviewer/model/map/species/Element.java
index b9b09c03c2d22c6e56b6c3710c166f57079f9319..386c2995adde11c9d6870a8b9b243c87ee696007 100644
--- a/model/src/main/java/lcsb/mapviewer/model/map/species/Element.java
+++ b/model/src/main/java/lcsb/mapviewer/model/map/species/Element.java
@@ -1096,6 +1096,7 @@ public abstract class Element implements AnnotatedObject, Serializable {
 		this.zoomLevelVisibility = zoomLevelVisibility;
 	}
 
+	@Override
 	public String getSemanticZoomLevelVisibility() {
 		return this.zoomLevelVisibility;
 	}