BuilderString.java

public class BuilderString {
     public static void main(String[] args) {
        StringBuilder sb = new StringBuilder("TomAndJerry");
        System.out.println(sb);

        //this charAt() helps to give only pointed letter 
        System.out.println(sb.charAt(0));

        //to change the letter
        //sb.setCharAt(index, ch);<-syntax
        sb.setCharAt(0, 'B');
        System.out.println(sb);//in upper line it has changed the value so thats why sb is uesed here

        //insert is used to insert letter in the word 
        sb.insert(2, 'o');
        System.out.println(sb);
        
        //.delete is used to delete form index number to wanted number
        sb.delete(2, 3);
        System.out.println(sb);

        //append meaning adding letter at last
        sb.append('N');
        sb.append('i');
        sb.append('n');
        sb.append('j');
        sb.append('a');
        System.out.println(sb);
    }
}