1 files changed, 6 insertions, 2 deletions
diff --git a/java/awt/ScrollPaneAdjustable.java b/java/awt/ScrollPaneAdjustable.java
index cfca19b44..bec5b5106 100644
--- a/java/awt/ScrollPaneAdjustable.java
+++ b/java/awt/ScrollPaneAdjustable.java
@@ -87,12 +87,16 @@ public class ScrollPaneAdjustable
   
   public void addAdjustmentListener (AdjustmentListener listener)
   {
-    AWTEventMulticaster.add (adjustmentListener, listener);
+    if (listener == null)
+      return;
+    adjustmentListener = AWTEventMulticaster.add (adjustmentListener, listener);
   }
   
   public void removeAdjustmentListener (AdjustmentListener listener)
   {
-    AWTEventMulticaster.remove (adjustmentListener, listener);
+    if (listener == null)
+      return;
+    adjustmentListener = AWTEventMulticaster.remove (adjustmentListener, listener);
   }
   
   public AdjustmentListener[] getAdjustmentListeners ()