this.writeBarrier = new DefaultWriteBarrier(helper);
this.writeBarrier = null;
	public DefaultHeapManager(VmClassLoader loader, HeapHelper helper, VmStatics statics) 	throws ClassNotFoundException {		super(helper);		this.writeBarrier = new DefaultWriteBarrier(helper);		this.firstHeap = new VmDefaultHeap(this);		this.currentHeap = firstHeap;		this.defaultHeapClass = (VmNormalClass)loader.loadClass(VmDefaultHeap.class.getName(), true);		this.statics = statics;	}