HashSet class

see Collection interface for descriptions and examples of all of HashSet's methods

■ This class implements the Set Interface, and extends the AbstractSet class. It is for everyday Set usage.

■ HashSet is for unordered Sets (with no duplicates allowed) in random or indeterminate order. So you can't control the order here. i.e. The snippet below will print 1 3 2 or 3 2 1, depending on your JVM, not 1 2 3 which is the order in which the three items were entered.

import java.util.*;

Set hs = new HashSet( );

hs.add("1");

hs.add("2");

hs.add("3");

System.out.println( hs );

■ HashSet’s everyday constructors:

HashSet hs = new HashSet( ); creates an empty set

HashSet hs = new HashSet(Collection); creates a set from any Collection