diff -r ccb1544a88bc -r 945c799a6812 javap/src/main/java/org/apidesign/javap/TrapDataIterator.java
--- a/javap/src/main/java/org/apidesign/javap/TrapDataIterator.java	Mon Dec 24 08:33:40 2012 +0100
+++ b/javap/src/main/java/org/apidesign/javap/TrapDataIterator.java	Sat Dec 29 20:10:10 2012 +0100
@@ -35,16 +35,20 @@
         }
     }
 
-    public void advanceTo(int i) {
+    public boolean advanceTo(int i) {
+        boolean change = false;
         Short s = Short.valueOf((short)i);
         TrapData e = (TrapData) exStart.get(s);
         if (e != null) {
             add(e);
+            change = true;
         }
         e = (TrapData) exStop.get(s);
         if (e != null) {
             remove(e);
+            change = true;
         }
+        return change;
     }
 
     public boolean useTry() {