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 Articles > Java > Basics > How to convert Long to Byte Array

How to convert Long to Byte Array 

The following example shows converting a Long to Byte array. Since a Java Long occupies 8 bytes allocate a ByteBuffer of capacity 8 and write the Long to ByteBuffer. It updates the ByteBuffer with 8 bytes representing the Long. Finally convert the ByteBuffer to byte array.

  • public static ByteBuffer allocate(int capacity)
    Allocates a new byte buffer of given capacity.
  • public ByteBuffer putLong(long value)
    Writes eight bytes containing the given long value to this ByteBuffer.
  • public final byte[] array()
    Returns the ByteBuffer as byte array.

File Name  :  
Author  :  Sudhakar KV
Email  :  [email protected]
package com.bethecoder.articles.basics.prim2bytea;

import java.nio.ByteBuffer;
import java.util.Arrays;

public class Long2ByteArrayTest {

   @param args
  public static void main(String[] args) {
    //Since long occupies 8 bytes allocate a buffer of size 8
    byte [] bytes = ByteBuffer.allocate(8).putLong(1729172917291729L).array();


It gives the following output,
[0, 6, 36, -84, 113, 125, -118, -47]



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