private void processChild(Object child) {
final void processChild(Object child) {
    private void processChild(Object child) {        final int gcColor = helper.getObjectColor(child);        if (gcColor <= GC_WHITE) {            // Yellow or White            helper.atomicChangeObjectColor(child, gcColor, GC_GREY);            try {                // TEST for a valid vmclass.                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");            }        }    }