diff --git a/jme3-core/src/main/java/com/jme3/animation/SkeletonControl.java b/jme3-core/src/main/java/com/jme3/animation/SkeletonControl.java
index f4d735f36..4a69c2d7c 100644
--- a/jme3-core/src/main/java/com/jme3/animation/SkeletonControl.java
+++ b/jme3-core/src/main/java/com/jme3/animation/SkeletonControl.java
@@ -110,7 +110,7 @@ public class SkeletonControl extends AbstractControl implements Cloneable, JmeCl
     /**
      * Material references used for hardware skinning
      */
-    private final HashSet<Material> materials = new HashSet<Material>();
+    private Set<Material> materials = new HashSet<Material>();
     
     /**
      * Serialization only. Do not use.