Java StringBuffer Example

StringBuffer Class is mutable sequence of characters.It's like String but content of String can be modified after creation.

Using StringBuffer different methods you can :

1. append String to existing String append() method
2. insert String at specific index using insert() method
3. reverse String using reverse() method.
4. Find character position within String
5. set character at Specific index
6. delete character at specific index
7. get subString using specific index
8. delete characters within String
9. find String buffer capacity

Java Program to StringBuffer methods example :
package com.anuj.io;

/**
 *
 * @author Anuj Patel
 */
public class StringBufferOperations {

    public static void main(String[] args) throws Exception {
        String str;
        try {
            str = ", This is the example of SringBuffer class and it's functions.";

            StringBuffer strbuf = new StringBuffer();
            strbuf.append(str);
            System.out.println(strbuf);
            strbuf.delete(0, str.length());

            //append element using StringBuffer
            strbuf.append("Hello");
            strbuf.append("World"); //print HelloWorld
            System.out.println(strbuf);

            //insert element using Stringbuffer
            strbuf.insert(5, "_Java "); //print Hello_Java World
            System.out.println(strbuf);

            //reverse element using String buffer
            strbuf.reverse();
            System.out.print("Reversed string : ");
            System.out.println(strbuf); //print dlroW avaJ_olleH
            strbuf.reverse();
            System.out.println(strbuf); //print Hello_Java World

            //setCharAt using StringBuffer
            strbuf.setCharAt(5, ' ');
            System.out.println(strbuf); //prit Hello Java World

            //find character position using StringBuffer
            System.out.print("Character at 6th position : ");
            System.out.println(strbuf.charAt(6)); //print J

            //get substring using StringBuffer
            System.out.print("Substring from position 3 to 6 : ");
            System.out.println(strbuf.substring(3, 7)); //print lo J

            //deleteCharAt specific index using StringBuffer
            strbuf.deleteCharAt(3);
            System.out.println(strbuf); //print Helo java World

            //Find StringBuffer Capacity
            System.out.print("Capacity of StringBuffer object : ");
            System.out.println(strbuf.capacity()); //print 21

            //delete characters using StringBuffer
            strbuf.delete(6, strbuf.length());
            System.out.println(strbuf); //no anything
        } catch (StringIndexOutOfBoundsException e) {
            System.out.println(e.getMessage());
        }
    }
}

Output :

run:
, This is the example of SringBuffer class and it's functions.
HelloWorld
Hello_Java World
Reversed string : dlroW avaJ_olleH
Hello_Java World
Hello Java World
Character at 6th position : J
Substring from position 3 to 6 : lo J
Helo Java World
Capacity of StringBuffer object : 62
Helo J
BUILD SUCCESSFUL (total time: 7 seconds)