CharBuffer asReadOnlyBuffer() method in Java

A read-only char buffer can be created using the contents of a buffer with the method asReadOnlyBuffer() in the class java.nio.CharBuffer. The new buffer cannot have any modifications as it is a read-only buffer. However, the capacity, positions, limits etc. of the new buffer are the same as the previous buffer.

A program that demonstrates this is given as follows −

Example

 Live Demo

import java.nio.*;
import java.util.*;
public class Demo {
   public static void main(String[] args) {
      int n = 5;
      try {
         CharBuffer buffer = CharBuffer.allocate(5);
         buffer.put('A');
         buffer.put('P');
         buffer.put('P');
         buffer.put('L');
         buffer.put('E');
         buffer.rewind();
         System.out.println("The Original CharBuffer is: " + Arrays.toString(buffer.array()));
         CharBuffer roBuffer = buffer.asReadOnlyBuffer();
         System.out.println("The ReadOnlyBuffer CharBuffer is: ");
         while (roBuffer.hasRemaining())
            System.out.print(roBuffer.get() + " ");
      } catch (IllegalArgumentException e) {
         System.out.println("Error!!! IllegalArgumentException");
      } catch (ReadOnlyBufferException e) {
         System.out.println("Error!!! ReadOnlyBufferException");
      }
   }
}

Output

The Original CharBuffer is: [A, P, P, L, E]
The ReadOnlyBuffer CharBuffer is:
A P P L E