HashSet Demo

package com.test.collection;import java.util.HashSet;import java.util.Iterator;import java.util.Set;public class SetTest {public static void main(String[] args) {Set<Integer> set = new HashSet<Integer>();set.add(123);set.add(456);System.out.println(set);set.remove(123);System.out.println(set);Iterator<Integer> it = set.iterator();while(it.hasNext()){System.out.println(it.next());}}}

[456, 123][456]456