return lhs.getPrimaryClass().getClassName().compareTo(rhs.getPrimaryClass().getClassName());
int cmp = lhs.getPrimaryClass().getClassName().compareTo(rhs.getPrimaryClass().getClassName()); if (cmp != 0) return cmp; return lhs.compareTo(rhs);
        public int compare(Object a, Object b) {            BugInstance lhs = (BugInstance) a;            BugInstance rhs = (BugInstance) b;            return lhs.getPrimaryClass().getClassName().compareTo(rhs.getPrimaryClass().getClassName());        }