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