java Random nextBytes() Method

Description

The nextBytes(byte[] bytes) method is used to generate random bytes and places them into a user-supplied byte array.

Declaration

Following is the declaration for java.util.Random.nextBytes() method.

public void nextBytes(byte[] bytes)

Parameters

• bytes −This is the non-null byte array in which to put the random bytes.

Return Value

NA

Exception

NA

Getting a Random Byte Array Example

The following example shows the usage of Java Random nextBytes() method. Firstly, we've created a Random object and then using nextBytes() we retrieved a random byte array and printed it.

package com.tutorialspoint;

import java.util.Random;

public class RandomDemo {
   public static void main( String args[] ) {
      
      // create random object
      Random randomNo = new Random();

      // create byte array
      byte[] nbyte = new byte[30];

      // put the next byte in the array
      randomNo.nextBytes(nbyte);

      // check the value of array   
      System.out.println("Value of byte array: ");
      
      for (int i = 0; i < nbyte.length; i++) {
         System.out.print(" " + nbyte[i] );
      }
   }      
}

Output

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

Value of byte array: 
 74 -7 25 110 -56 -112 -95 -56 28 27 -59 -52 -64 2 -73 123 100 22 -42 -51 79 -63 -53 4 53 -78 -54 25 -51 -15

Getting a Random Byte Array with a Given Seed Example

The following example shows the usage of Java Random nextBytes() method. Firstly, we've created a Random object with a seed value and then using nextBytes() we retrieved a random byte array and printed it.

package com.tutorialspoint;

import java.util.Random;

public class RandomDemo {
   public static void main( String args[] ) {
      
      // create random object
      Random randomNo = new Random();

      // create byte array
      byte[] nbyte = new byte[30];

      // put the next byte in the array
      randomNo.nextBytes(nbyte);

      // check the value of array   
      System.out.println("Value of byte array: ");
      
      for (int i = 0; i < nbyte.length; i++) {
         System.out.print(" " + nbyte[i] );
      }
   }      
}

Output

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

Value of byte array: 
 97 -11 79 -8 -120 109 -34 -111 113 -84 27 96 -127 118 -115 103 -73 83 110 -82 36 77 36 -72 -22 89 23 83 -111 -93