StringBuffer can add new characters sequence in the String with the help of insert() method in java. insert() function insert characters in the String at particular index number in character sequence of the StringBuffer. StringBuffer insert is fastest way to insert String characters. Use of String insert() in java is shown below.

Example of StringBuffer insert() in java, JSP

public class StringBufferInsertExample {

    public static void main(String[] args) {

        StringBuffer sb = new StringBuffer("Java insert");

        System.out.println("Output :"+sb);

        sb.insert(5,"StringBuffer ");

        System.out.println("Output :"+sb);
    }
}

Output