java detector

    @SuppressWarnings("unchecked")
    private Set<JLPFlag> checkFlags() {
        Set<JLPFlag> flags = EnumSet.allOf(JLPFlag.class);
        // store the last state
        List<T> prev = new ArrayList<T>(backing);
        List<T> list = backing;
        if (list instanceof Cloneable) {
            // no promise this works, see Clonable javadocs
            Method clone;
            try {
                clone = list.getClass().getDeclaredMethod("clone");
                list = (List<T>) clone.invoke(list);
            } catch (Exception e) {
                System.err.println("No clone: " + e.getClass());
            }
        }
        if (list == backing && list instanceof Serializable) {
            list = (List<T>) cloneLikeSerial((Serializable) list);
        }
        boolean empty = list.isEmpty();
        try {
            if (!empty) {
                list.add(list.get(0));
            } else {
                // hope that list allows null
                list.add(null);
            }
        } catch (Exception e) {
            flags.remove(JLPFlag.ADD);
        }
        try {
            list.set(0, list.get(1));
        } catch (Exception e) {
            flags.remove(JLPFlag.SET);
        }
        try {
            list.remove(0);
        } catch (Exception e) {
            flags.remove(JLPFlag.REMOVE);
        }
        if (flags.contains(JLPFlag.REMOVE) && list == backing)
            list.clear();
        if (flags.contains(JLPFlag.ADD) && list == backing)
            list.addAll(prev);
        return flags;
    }