diff --git a/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessor.java b/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessor.java
index e302b82b1c..0758f2d0a9 100644
--- a/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessor.java
+++ b/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessor.java
@@ -50,10 +50,10 @@ public interface ChangesetPreProcessor
 {
 
   /**
-   * Method description
+   * Process the given changeset.
    *
    *
-   * @param changeset
+   * @param changeset changeset to process
    */
   public void process(Changeset changeset);
 }
diff --git a/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessorFactory.java b/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessorFactory.java
index 47f0a7ccd7..47ab5786e2 100644
--- a/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessorFactory.java
+++ b/scm-core/src/main/java/sonia/scm/repository/ChangesetPreProcessorFactory.java
@@ -51,12 +51,12 @@ public interface ChangesetPreProcessorFactory
 {
 
   /**
-   * Method description
+   * Create a new {@link ChangesetPreProcessor} for the given repository.
    *
    *
-   * @param repository
+   * @param repository repository
    *
-   * @return
+   * @return {@link ChangesetPreProcessor} for the given repository
    */
   public ChangesetPreProcessor createPreProcessor(Repository repository);
 }
diff --git a/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessor.java b/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessor.java
index 175020bf6c..0e6560136f 100644
--- a/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessor.java
+++ b/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessor.java
@@ -38,6 +38,9 @@ package sonia.scm.repository;
 import sonia.scm.plugin.ExtensionPoint;
 
 /**
+ * A pre processor for {@link FileObject} objects. A pre processor is able to 
+ * modify the object before it is delivered to the user interface.
+ * 
  * TODO for 2.0 extends {@link PreProcessor} interface.
  * 
  * @author Sebastian Sdorra
@@ -48,10 +51,10 @@ public interface FileObjectPreProcessor
 {
 
   /**
-   * Method description
+   * Process the given file object.
    *
    *
-   * @param fileObject
+   * @param fileObject file object to process
    */
   public void process(FileObject fileObject);
 }
diff --git a/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessorFactory.java b/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessorFactory.java
index 0875a092c6..746aed75f3 100644
--- a/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessorFactory.java
+++ b/scm-core/src/main/java/sonia/scm/repository/FileObjectPreProcessorFactory.java
@@ -38,6 +38,9 @@ package sonia.scm.repository;
 import sonia.scm.plugin.ExtensionPoint;
 
 /**
+ * The FileObjectPreProcessorFactory create {@link FileObjectPreProcessor}
+ * objects for a specific repository.
+ * 
  * TODO for 2.0 extends {@link PreProcessorFactory} interface.
  *
  * @author Sebastian Sdorra
@@ -48,12 +51,12 @@ public interface FileObjectPreProcessorFactory
 {
 
   /**
-   * Method description
+   * Create a new {@link FileObjectPreProcessor} for the given repository.
    *
    *
-   * @param repository
+   * @param repository repository
    *
-   * @return
+   * @return {@link FileObjectPreProcessor} for the given repository
    */
   public FileObjectPreProcessor createPreProcessor(Repository repository);
 }
diff --git a/scm-core/src/main/java/sonia/scm/repository/PreProcessor.java b/scm-core/src/main/java/sonia/scm/repository/PreProcessor.java
index cdfd711a87..992f5b07e6 100644
--- a/scm-core/src/main/java/sonia/scm/repository/PreProcessor.java
+++ b/scm-core/src/main/java/sonia/scm/repository/PreProcessor.java
@@ -33,20 +33,22 @@
 package sonia.scm.repository;
 
 /**
+ * A pre processor is able to modify a object before it is delivered 
+ * to the user interface.
  *
  * @author Sebastian Sdorra
  * @since 1.17
  *
- * @param <T>
+ * @param <T> object type
  */
 public interface PreProcessor<T>
 {
 
   /**
-   * Method description
+   * Process the given object.
    *
    *
-   * @param item
+   * @param item object to process
    */
   public void process(T item);
 }
diff --git a/scm-core/src/main/java/sonia/scm/repository/PreProcessorFactory.java b/scm-core/src/main/java/sonia/scm/repository/PreProcessorFactory.java
index 4bf90ec1c6..91a452d1bc 100644
--- a/scm-core/src/main/java/sonia/scm/repository/PreProcessorFactory.java
+++ b/scm-core/src/main/java/sonia/scm/repository/PreProcessorFactory.java
@@ -30,25 +30,28 @@
  */
 
 
+
 package sonia.scm.repository;
 
 /**
+ * A pre processor factory creates a specific {@link PreProcessor} for
+ * the given repository.
  *
  * @author Sebastian Sdorra
  *
- * @param <T>
+ * @param <T> object type for the {@link PreProcessor}
  * @since 1.17
  */
 public interface PreProcessorFactory<T>
 {
 
   /**
-   * Method description
+   * Create a new {@link PreProcessor} for the given repository.
    *
    *
-   * @param repository
+   * @param repository repository
    *
-   * @return
+   * @return {@link PreProcessor} for the given repository
    */
   public PreProcessor<T> createPreProcessor(Repository repository);
 }