Java.lang.StringBuilder.append() Method



The java.lang.StringBuilder.append(char[] str, int offset, int len) method appends the string representation of a subarray of the char array argument to this sequence.

Characters of the char array str, starting at index offset, are appended, in order, to the contents of this sequence. The length of this sequence increases by the value of len.


Following is the declaration for java.lang.StringBuilder.append() method

public StringBuilder append(char[] str, int offset, int len)


  • str − This is the characters to be appended.

  • offset − This is the index of the first char to append.

  • len − This is the number of chars to append.

Return Value

This method returns a reference to this object.




The following example shows the usage of java.lang.StringBuilder.append() method.

package com.tutorialspoint;

import java.lang.*;

public class StringBuilderDemo {

   public static void main(String[] args) {
      StringBuilder str = new StringBuilder("amrood ");
      System.out.println("string = " + str);
      // char array
      char[] cArr = new char[]
      /* appends the string representation of char array argument to
         this StringBuilder with offset at index 0 and length as 5 */
      str.append(cArr, 0, 5);
      // print the StringBuilder after appending
      System.out.println("After append = " + str);

Let us compile and run the above program, this will produce the following result −

string = amrood
After append = amrood admin