diff --git a/ccm-cms/src/main/java/org/librecms/assets/AbstractBinaryAssetImExporter.java b/ccm-cms/src/main/java/org/librecms/assets/AbstractBinaryAssetImExporter.java
index 58d1cb43a..9641e8e00 100644
--- a/ccm-cms/src/main/java/org/librecms/assets/AbstractBinaryAssetImExporter.java
+++ b/ccm-cms/src/main/java/org/librecms/assets/AbstractBinaryAssetImExporter.java
@@ -20,7 +20,6 @@ package org.librecms.assets;
 
 import java.util.Objects;
 
-
 /**
  *
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
@@ -29,15 +28,42 @@ import java.util.Objects;
 public abstract class AbstractBinaryAssetImExporter<T extends BinaryAsset>
     extends AbstractAssetImExporter<T> {
 
+    /**
+     * Implementation of
+     * {@link AbstractBinaryAssetImExporter#initAssetImExporter()} for subtypes
+     * of {@link BinaryAsset}.
+     *
+     * !!!Warning: Implementations of this abstract class MUST NEVER override
+     * this method. Instead they MUST implement
+     * {@link #initBinaryAssetImExporter()}.
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     */
     @Override
-    protected final void initAssetImExporter() {
+    protected void initAssetImExporter() {
         initBinaryAssetImExporter();
     }
 
     protected abstract void initBinaryAssetImExporter();
 
+    /**
+     * Implementation of
+     * {@link AbstractAssetImExporter#updateExistingAsset(org.librecms.contentsection.Asset, org.librecms.contentsection.Asset)}
+     * for subtypes of {@link BinaryAsset}.
+     *
+     * Implementations of this abstract class MUST NEVER override this method.
+     * Instead, they MUST implement
+     * {@link #updateExistingBinaryAsset(org.librecms.assets.BinaryAsset, org.librecms.assets.BinaryAsset)}.
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     *
+     * @param existingAsset
+     * @param importedAsset
+     */
     @Override
-    protected final void updateExistingAsset(
+    protected void updateExistingAsset(
         final T existingAsset,
         final T importedAsset
     ) {
diff --git a/ccm-cms/src/main/java/org/librecms/assets/AbstractBookmarkImExporter.java b/ccm-cms/src/main/java/org/librecms/assets/AbstractBookmarkImExporter.java
index bc1f8d7ad..02fc5caad 100644
--- a/ccm-cms/src/main/java/org/librecms/assets/AbstractBookmarkImExporter.java
+++ b/ccm-cms/src/main/java/org/librecms/assets/AbstractBookmarkImExporter.java
@@ -20,7 +20,6 @@ package org.librecms.assets;
 
 import java.util.Objects;
 
-
 /**
  *
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
@@ -29,14 +28,39 @@ import java.util.Objects;
 public abstract class AbstractBookmarkImExporter<T extends Bookmark>
     extends AbstractAssetImExporter<T> {
 
-    
+    /**
+     * Implementation of {@link AbstractAssetImExporter#initAssetImExporter()}
+     * for {@link Bookmark} and subtypes of {@link Bookmark}.
+     *
+     * !!!Warning: Implementations of this abstract class MUST NEVER override
+     * this method. Instead, they MUST implement {@link #initBookmarkImExporter()
+     * }.
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     */
     @Override
     protected final void initAssetImExporter() {
         initBookmarkImExporter();
     }
-    
+
     protected abstract void initBookmarkImExporter();
-    
+
+    /**
+     * Implementation of {@link AbstractAssetImExporter#updateExistingAsset(org.librecms.contentsection.Asset, org.librecms.contentsection.Asset)
+     * }
+     * for {@link Bookmark} and subtypes of {@link Bookmark}.
+     *
+     * !!!Warning: Implementations of this abstract class MUST NEVER override
+     * this method. Instead, they MUST implement
+     * {@link #updateExistingBookmark(org.librecms.assets.Bookmark, org.librecms.assets.Bookmark)}.
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     *
+     * @param existingAsset
+     * @param importedAsset
+     */
     @Override
     protected final void updateExistingAsset(
         final T existingAsset,
@@ -47,24 +71,24 @@ public abstract class AbstractBookmarkImExporter<T extends Bookmark>
             importedAsset.getDescription()
         )) {
             syncLocalizedStrings(
-                importedAsset.getDescription(), 
+                importedAsset.getDescription(),
                 existingAsset.getDescription()
             );
-        } 
-        
+        }
+
         if (!Objects.equals(
             existingAsset.getUrl(),
             importedAsset.getUrl()
         )) {
             existingAsset.setUrl(importedAsset.getUrl());
         }
-        
+
         updateExistingBookmark(existingAsset, importedAsset);
     }
-    
+
     protected abstract void updateExistingBookmark(
         final T existingBookmark,
         final T importedBookmark
     );
-    
+
 }
diff --git a/ccm-cms/src/main/java/org/librecms/assets/AbstractContactableEntityImExporter.java b/ccm-cms/src/main/java/org/librecms/assets/AbstractContactableEntityImExporter.java
index f03bc451e..c2e94202f 100644
--- a/ccm-cms/src/main/java/org/librecms/assets/AbstractContactableEntityImExporter.java
+++ b/ccm-cms/src/main/java/org/librecms/assets/AbstractContactableEntityImExporter.java
@@ -29,8 +29,19 @@ import java.util.Set;
 public abstract class AbstractContactableEntityImExporter<T extends ContactableEntity>
     extends AbstractAssetImExporter<T> {
 
+    /**
+     * Implementation of {@link AbstractAssetImExporter#initAssetImExporter()}
+     * for subtypes of {@link ContactableEntity}.
+     *
+     * !!!Warning: Implementations of this abstract class MUST NEVER override
+     * this method. Instead, they MUST override
+     * {@link #initContactableEntityImExporter()}
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     */
     @Override
-    protected final void initAssetImExporter() {
+    protected void initAssetImExporter() {
         addRequiredEntities(Set.of(PostalAddress.class));
 
         initContactableEntityImExporter();
@@ -38,8 +49,24 @@ public abstract class AbstractContactableEntityImExporter<T extends ContactableE
 
     protected abstract void initContactableEntityImExporter();
 
+    /**
+     * Implementation of
+     * {@link AbstractAssetImExporter#updateExistingAsset(org.librecms.contentsection.Asset, org.librecms.contentsection.Asset)}
+     * for subtypes of {@link ContactableEntity}.
+     *
+     * !!!Warning: Implemementations of this abstract class MUST NEVER override
+     * this method. Instead, they MUST implement
+     * {@link #updateExistingContactable(org.librecms.assets.ContactableEntity, org.librecms.assets.ContactableEntity)}.
+     *
+     *
+     * Unfortunetly, CDI does not support final methods, therefore we can't make
+     * this method final.
+     *
+     * @param existingAsset
+     * @param importedAsset
+     */
     @Override
-    protected final void updateExistingAsset(
+    protected void updateExistingAsset(
         final T existingAsset,
         final T importedAsset
     ) {