diff --git a/ccm-core/src/main/java/org/libreccm/api/themes/Themes.java b/ccm-core/src/main/java/org/libreccm/api/themes/Themes.java
index 17891cf84..218ab2f49 100644
--- a/ccm-core/src/main/java/org/libreccm/api/themes/Themes.java
+++ b/ccm-core/src/main/java/org/libreccm/api/themes/Themes.java
@@ -20,7 +20,6 @@ package org.libreccm.api.themes;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.hibernate.engine.jdbc.internal.BinaryStreamImpl;
 import org.libreccm.core.UnexpectedErrorException;
 import org.libreccm.security.AuthorizationRequired;
 import org.libreccm.security.RequiresPrivilege;
@@ -36,12 +35,9 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.Serializable;
-import java.rmi.UnexpectedException;
-import java.security.DigestInputStream;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
@@ -73,6 +69,7 @@ import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 
 /**
+ * Provides a RESTful API for managing themes.
  *
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
  */
@@ -84,17 +81,25 @@ public class Themes implements Serializable {
 
     private static final Logger LOGGER = LogManager.getLogger(Themes.class);
 
+    /**
+     * The available theme providers.
+     */
     @Inject
     @Any
     private Instance<ThemeProvider> providers;
 
+    /**
+     * Lists the available theme providers.
+     *
+     * @return A list of the fully qualified class names of the available theme
+     *         providers.
+     */
     @GET
     @Path("/providers")
     @Produces(MediaType.APPLICATION_JSON)
     @AuthorizationRequired
     @RequiresPrivilege(ThemingPrivileges.ADMINISTER_THEMES)
     public List<String> getThemeProviders() {
-
         return providers
             .stream()
             .filter(
@@ -105,6 +110,11 @@ public class Themes implements Serializable {
             .collect(Collectors.toList());
     }
 
+    /**
+     * Gets a list of all available themes.
+     *
+     * @return A list of all available themes.
+     */
     @GET
     @Path("/themes")
     @Produces(MediaType.APPLICATION_JSON)
@@ -121,6 +131,13 @@ public class Themes implements Serializable {
             .collect(Collectors.toList());
     }
 
+    /**
+     * Gets the {@link ThemeInfo} for a specific theme.
+     *
+     * @param themeName The name of the theme.
+     *
+     * @return The {@link ThemeInfo} for the theme.
+     */
     @GET
     @Path("/themes/{theme}")
     @Produces(MediaType.APPLICATION_JSON)
@@ -156,6 +173,15 @@ public class Themes implements Serializable {
             );
     }
 
+    /**
+     * Creates a new theme.
+     *
+     * @param themeName    The name of the new theme.
+     *
+     * @param providerName The provider to use for the new theme.
+     *
+     * @return The {@link ThemeInfo} for the new theme.
+     */
     @PUT
     @Path("/themes/{theme}")
     @Produces(MediaType.APPLICATION_JSON)
@@ -193,6 +219,13 @@ public class Themes implements Serializable {
         return provider.createTheme(themeName);
     }
 
+    /**
+     * Deletes a theme.
+     *
+     * @param themeName The theme to delete.
+     *
+     * @return A response indicating success or failure.
+     */
     @DELETE
     @Path("/themes/{theme}")
     @AuthorizationRequired
@@ -214,6 +247,13 @@ public class Themes implements Serializable {
         return Response.ok().build();
     }
 
+    /**
+     * Publishes a theme.
+     *
+     * @param themeName The name of theme to publish.
+     *
+     * @return A response indicating success or failure.
+     */
     @POST
     @Path("/themes/{theme}/live")
     @AuthorizationRequired
@@ -233,6 +273,13 @@ public class Themes implements Serializable {
         return Response.ok().build();
     }
 
+    /**
+     * Unpublishes a theme.
+     *
+     * @param themeName The name of theme to unpublish.
+     *
+     * @return A response indicating success or failure.
+     */
     @DELETE
     @Path("/themes/{theme}/live")
     @AuthorizationRequired
@@ -252,6 +299,13 @@ public class Themes implements Serializable {
         return Response.ok().build();
     }
 
+    /**
+     * Gets the files in the root directory of the theme.
+     *
+     * @param themeName The name of the name.
+     *
+     * @return A list of files in the root directory of the theme.
+     */
     @GET
     @Path("/themes/{theme}/files/")
     @AuthorizationRequired
@@ -294,6 +348,14 @@ public class Themes implements Serializable {
         }
     }
 
+    /**
+     * Gets a file from the theme.
+     *
+     * @param themeName The name of the theme.
+     * @param path      The path of the file to retrieve.
+     *
+     * @return The content of the requsted file.
+     */
     @GET
     @Path("/themes/{theme}/files/{path:.+}")
     @AuthorizationRequired
@@ -350,6 +412,15 @@ public class Themes implements Serializable {
         }
     }
 
+    /**
+     * Creates or updates a file in a theme.
+     *
+     * @param themeName The name of the theme.
+     * @param path      The path of file to create or update.
+     * @param data      The contents of the file.
+     *
+     * @return A response indicating success or failure.
+     */
     @PUT
     @Path("/themes/{theme}/files/{path:.+}")
     @AuthorizationRequired
@@ -401,6 +472,16 @@ public class Themes implements Serializable {
         return Response.ok().build();
     }
 
+    /**
+     * Removes a file from a theme
+     *
+     * @param themeName The name of the theme.
+     * @param path      The path of the file to delete.
+     * @param recursive If the file is a directory: Delete the directory and all
+     *                  its content?
+     *
+     * @return A response indicating success or failure.
+     */
     @DELETE
     @Path("/themes/{theme}/files/{path:.+}")
     @AuthorizationRequired
@@ -457,6 +538,13 @@ public class Themes implements Serializable {
         }
     }
 
+    /**
+     * Downloads a theme as ZIP file.
+     *
+     * @param themeName The name of the theme to download.
+     *
+     * @return A response with a ZIP file containing all files or the theme.
+     */
     @GET
     @Path("/themes/{theme}/@download")
     @Produces("application/zip")
@@ -492,6 +580,24 @@ public class Themes implements Serializable {
         }
     }
 
+    /**
+     * Updates a theme from a ZIP file. The method checks each file in the ZIP
+     * and in the theme and does to following:
+     * <ul>
+     * <li>If the files (their checksums) are identical, do nothing</li>
+     * <li>If the checksums differ: Update the file in the theme with the file
+     * from the ZIP file.</li>
+     * <li>If the file exists only in the ZIP: Create the file in the
+     * theme.</li>
+     * <li>If the file exists only in the theme: Remove the file from the
+     * theme.</li>
+     * </ul>
+     *
+     * @param themeName    The name of the theme to update.
+     * @param updatedTheme The ZIP file containing the updated theme.
+     *
+     * @return A response indicating success or failure.
+     */
     @POST
     @Path("/themes/{theme}/@update")
     @Consumes("application/zip")
@@ -558,7 +664,7 @@ public class Themes implements Serializable {
                     if (!MessageDigest.isEqual(
                         fromZipChecksum, fromThemeChecksum
                     )) {
-                        try(OutputStream outputStream = provider
+                        try (OutputStream outputStream = provider
                             .getOutputStreamForThemeFile(themeName, path)) {
                             outputStream.write(bytesFromZip);
                         }