stack.push(child);
try {  helper.getVmClass(child); stack.push(child); } catch (NullPointerException ex) { Unsafe.debug("\nObject address "); Unsafe.debug(helper.addressOf32(child)); Unsafe.debug("\nObject TIB "); Unsafe.debug(helper.addressOf32(helper.getTib(child))); helper.die("NPE in processChild; probably corrupted heap"); }
    private void processChild(Object child) {        final int gcColor = helper.getObjectColor(child);        if (gcColor <= GC_WHITE) {            // Yellow or White            helper.atomicChangeObjectColor(child, gcColor, GC_GREY);            stack.push(child);        }    }