Java StringBuilder

StringBuilder sb=new StringBuilder();
sb.append("String1");
sb.append("String2");
sb.append("String3");

package com.java.myapp;

public class MyClass {

    public static void main(String[] args) {
    
    	StringBuilder aVar = new StringBuilder();
		aVar.append(" String  1");
		aVar.append(" String  2");
		aVar.append(" String  3");
		System.out.println(aVar);
		
		System.out.println("Length = " + aVar.length());
		
		aVar.reverse();
		System.out.println(aVar);
    	    	
    }
	
}