// A StringBuffer is a mutable sequence of characters. It is used to create and manipulate strings.

// Unlike String class, StringBuffer provides methods to modify the contents of the string without creating a new object.

​

// Here's an example of using StringBuffer to concatenate multiple strings:

StringBuffer stringBuffer = new StringBuffer();

stringBuffer.append("Hello ");

stringBuffer.append("World!");

​

System.out.println(stringBuffer.toString()); // Output: Hello World!

// Java Program showcasing some of StringBuffer class capabilities

import java.io.*;

class StringBufferDemo {

     public static void main(String[] args) {

        // Creating StringBuffer object

        StringBuffer s = new StringBuffer("Dummy value");

        // Getting the length of object

        int length = s.length();

        // Getting the capacity of object

        int capacity = s.capacity();

        // Printing the length and capacity of

        System.out.println("Length of string buffer = "

                           + length); // 11

        System.out.println(

            "Capacity of string buffer = " + capacity); // 27

        // append method

        s.append(" appended");

        System.out.println(s); // Dummy value appended

        // insert method

        s.insert(s.length(), " for illustration."); 

        System.out.println(s); // Dummy value appended for illustration.

        // delete method

        s.delete(0, 6);

        System.out.println(s); // value appended for illustration.

        // deleteCharAt method

        s.deleteCharAt(0);

        System.out.println(s); // alue appended for illustration.

        // reverse method

        s.reverse();

        System.out.println(s); // .noitartsulli rof dedneppa eula

    }

}

Internet Explorer is the only browser which really suffers from this in today's world. (Versions 5, 6, and 7 were dog slow. 8 does not show the same degradation.) What's more, IE gets slower and slower the longer your string is.

​

If you have long strings to concatenate then definitely use an array.join technique. (Or some StringBuffer wrapper around this, for readability.) But if your strings are short don't bother.

String third = first + second;

​

​