SynchronizedCollection(Collection<E> c) 
{
            if (c==null)
                throw new NullPointerException();
            this.c = c;
            mutex = this;
}

 SynchronizedCollection(Collection<E> c,
    Object mutex) 
{
            this.c = c;
            this.mutex = mutex;
}

 public boolean add(E e) 
{
            synchronized (mutex) {return c.add(e);}
}

 public boolean addAll(Collection<? extends E> coll) 
{
            synchronized (mutex) {return c.addAll(coll);}
}

 public  void clear() 
{
            synchronized (mutex) {c.clear();}
}

 public boolean contains(Object o) 
{
            synchronized (mutex) {return c.contains(o);}
}

 public boolean containsAll(Collection<?> coll) 
{
            synchronized (mutex) {return c.containsAll(coll);}
}

 public boolean isEmpty() 
{
            synchronized (mutex) {return c.isEmpty();}
}

 public Iterator<E> iterator() 
{
            return c.iterator(); // Must be manually synched by user!
}

 public boolean remove(Object o) 
{
            synchronized (mutex) {return c.remove(o);}
}

 public boolean removeAll(Collection<?> coll) 
{
            synchronized (mutex) {return c.removeAll(coll);}
}

 public boolean retainAll(Collection<?> coll) 
{
            synchronized (mutex) {return c.retainAll(coll);}
}

 public int size() 
{
            synchronized (mutex) {return c.size();}
}

 public Object[] toArray() 
{
            synchronized (mutex) {return c.toArray();}
}

 public T[] toArray(T[] a) 
{
            synchronized (mutex) {return c.toArray(a);}
}

 public String toString() 
{
            synchronized (mutex) {return c.toString();}
}