DoubleBuffer hasArray() method in Java

It can be checked if a buffer has the backing of an accessible double array by using the method hasArray() in the class java.nio.DoubleBuffer. This method returns true if the buffer has the backing of an accessible double array and false otherwise.

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 {
         DoubleBuffer buffer = DoubleBuffer.allocate(5);
         buffer.put(4.5D);
         buffer.put(1.2D);
         buffer.put(3.9D);
         buffer.put(7.5D);
         buffer.put(5.8D);
         buffer.rewind();
         System.out.println("The DoubleBuffer is: " + Arrays.toString(buffer.array()));
         boolean flag = buffer.hasArray();
         if (flag)
            System.out.println("The DoubleBuffer is backed by an array");
         else
            System.out.println("The DoubleBuffer is not backed by any array");
      } catch (IllegalArgumentException e) {
         System.out.println("Error!!! IllegalArgumentException");
      } catch (ReadOnlyBufferException e) {
         System.out.println("Error!!! ReadOnlyBufferException");
      }
   }
}

The output of the above program is as follows −

Output

The DoubleBuffer is: [4.5, 1.2, 3.9, 7.5, 5.8]
The DoubleBuffer is backed by an array