Index: trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 16566)
+++ trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 16567)
@@ -2,4 +2,5 @@
 package org.openstreetmap.josm.data;
 
+import java.util.Collections;
 import java.util.EventObject;
 import java.util.LinkedList;
@@ -238,8 +239,8 @@
      * Returns all commands that were made on the dataset, that can be undone.
      * @return all commands that were made on the dataset, that can be undone
-     * @since 14281
-     */
-    public LinkedList<Command> getUndoCommands() {
-        return new LinkedList<>(commands);
+     * @since 14281, 16567 (signature)
+     */
+    public List<Command> getUndoCommands() {
+        return Collections.unmodifiableList(commands);
     }
 
@@ -247,8 +248,8 @@
      * Returns all commands that were made and undone on the dataset, that can be redone.
      * @return all commands that were made and undone on the dataset, that can be redone.
-     * @since 14281
-     */
-    public LinkedList<Command> getRedoCommands() {
-        return new LinkedList<>(redoCommands);
+     * @since 14281, 16567 (signature)
+     */
+    public List<Command> getRedoCommands() {
+        return Collections.unmodifiableList(redoCommands);
     }