return Collections.unmodifiableMap(new HashMap(this)).entrySet();
HashMap copy = new HashMap(); for (Iterator it = keySet().iterator(); it.hasNext();) { Object key = it.next(); copy.put(key, get(key)); } return Collections.unmodifiableMap(copy).entrySet();
    public Set entrySet() {        return Collections.unmodifiableMap(new HashMap(this)).entrySet();    }