Native byte order on your machine

Simple, in JDK1.4+, use java.nio.ByteOrder.nativeOrder()

Main.java:

import java.nio.*;
 
public class Main
{
   public static void main(String []args) {
      ByteOrder bo = ByteOrder.nativeOrder();
      
      System.out.println("Native byte order of your platform is " + bo);
   }
}

outputs on my win machine:

Native byte order of your platform is LITTLE_ENDIAN