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