1 
2 package java.util;
3 
4 public interface Set extends Collection
5     {
6 
size()7     public int size();
isEmpty()8     public boolean isEmpty();
contains(Object o)9     public boolean contains(Object o);
iterator()10     public Iterator iterator();
toArray()11     public Object[] toArray();
toArray(Object[] a)12     public Object[] toArray(Object[] a);
add(Object o)13     public boolean add(Object o);
remove(Object o)14     public boolean remove(Object o);
containsAll(Collection c)15     public boolean containsAll(Collection c);
addAll(Collection c)16     public boolean addAll(Collection c);
retainAll(Collection c)17     public boolean retainAll(Collection c);
removeAll(Collection c)18     public boolean removeAll(Collection c);
clear()19     public void clear();
equals(Object o)20     public boolean equals(Object o);
hashCode()21     public int hashCode();
22 
23 
24 
25 
26   }
27