pure interface of class java.util.AbstractCollection<A>

public abstract class AbstractCollection<A>
  implements Collection<A>
{
    public abstract Iterator<A> iterator();
    public abstract int size();
    public boolean isEmpty();
    public boolean contains(A o);
    public Object[] toArray();
    public A[] toArray(A[] a);
    public boolean add(A o);
    public boolean remove(A o);
    public boolean containsAll(Collection<A> c);
    public boolean addAll(Collection<A> c);
    public boolean removeAll(Collection<A> c);
    public boolean retainAll(Collection<A> c);
    public void clear();
    public String toString();
    public AbstractCollection();
}