ByteBuffer allocate() method in Java

A new ByteBuffer can be allocated using the method allocate() in the class java.nio.ByteBuffer. This method requires a single parameter i.e. the capacity of the buffer. It returns the new ByteBuffer that is allocated. If the capacity provided is negative, then the IllegalArgumentException is thrown.

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 {
         ByteBuffer buffer = ByteBuffer.allocate(n);
         buffer.put((byte)1);
         buffer.put((byte)2);
         buffer.put((byte)3);
         buffer.put((byte)4);
         buffer.put((byte)5);
         buffer.rewind();
         System.out.println("The ByteBuffer is: " + Arrays.toString(buffer.array()));
      } catch (IllegalArgumentException e) {
         System.out.println("Error!!! IllegalArgumentException");
      } catch (ReadOnlyBufferException e) {
         System.out.println("Error!!! ReadOnlyBufferException");
      }
   }
}

Output

The ByteBuffer is: [1, 2, 3, 4, 5]