mutable string in java

/**
 * @author lautturi.com 
 * Java example: create a mutable string in java
 */

import java.util.*;

public class Lautturi {
	public static void main(String args[]) {
		StringBuilder mutableStr = new StringBuilder("hello java"); 
		mutableStr.append(" world") ;
		System.out.println(mutableStr);
		mutableStr.append(" lautturi") ;
		System.out.println(mutableStr);
		
		String str = mutableStr.toString();
		System.out.println(str);
		
	}
}

output:

hello java world
hello java world lautturi
hello java world lautturi