--- old/agent/src/share/classes/sun/jvm/hotspot/gc_implementation/g1/HeapRegionSetBase.java	2014-02-11 11:34:03.897495784 +0100
+++ new/agent/src/share/classes/sun/jvm/hotspot/gc_implementation/g1/HeapRegionSetBase.java	2014-02-11 11:34:03.817495783 +0100
@@ -40,12 +40,8 @@
 // Mirror class for HeapRegionSetBase. Represents a group of regions.
 
 public class HeapRegionSetBase extends VMObject {
-    // uint _length;
-    static private CIntegerField lengthField;
-    // uint _region_num;
-    static private CIntegerField regionNumField;
-    // size_t _total_used_bytes;
-    static private CIntegerField totalUsedBytesField;
+
+    static private long countField;
 
     static {
         VM.registerVMInitializedObserver(new Observer() {
@@ -58,23 +54,16 @@
     static private synchronized void initialize(TypeDataBase db) {
         Type type = db.lookupType("HeapRegionSetBase");
 
-        lengthField         = type.getCIntegerField("_length");
-        regionNumField      = type.getCIntegerField("_region_num");
-        totalUsedBytesField = type.getCIntegerField("_total_used_bytes");
+        countField = type.getField("_count").getOffset();
     }
 
-    public long length() {
-        return lengthField.getValue(addr);
-    }
 
-    public long regionNum() {
-        return regionNumField.getValue(addr);
+    public HeapRegionSetCount count() {
+        Address countFieldAddr = addr.addOffsetTo(countField);
+        return (HeapRegionSetCount) VMObjectFactory.newObject(HeapRegionSetCount.class,
+        		                                              countFieldAddr);
     }
-
-    public long totalUsedBytes() {
-        return totalUsedBytesField.getValue(addr);
-    }
-
+    
     public HeapRegionSetBase(Address addr) {
         super(addr);
     }