Java Program on Mutable Class and StringBuffer Class

Program 1

package dataflair;

public class TestBuffer 
{
    public static void main(String[] args) 
    {
//       String S="Data Flair Free Course";// immutable
//       S.concat("Indore");
//       System.out.println(S);
        
       StringBuffer sb=new StringBuffer("Data Flair Free Course");
       //System.out.println(sb.substring(5,10));
        //sb.deleteCharAt(5);
        sb.delete(5,10);
        System.out.println(sb);
        //System.out.println(sb.charAt(5));
        // StringBuffer sb=new StringBuffer("Data Flair");
        // System.out.println(sb.capacity());
        // System.out.println(sb.length());
        //System.out.println(sb);
       // sb.append(" Indore");
       // System.out.println(sb);
        //sb.insert(10, " Complete");
       // System.out.println(sb);
        // sb.replace(3, 7, "ABCDEF");
//        sb.reverse();
//        System.out.println(sb);
        
    }
    
}