Here you can find the source of uuidToBytes(UUID uuid)
public static byte[] uuidToBytes(UUID uuid)
//package com.java2s; /*//from ww w.j a v a 2 s.c om * Copyright (c) 2016 acmi * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.util.UUID; public class Main { public static byte[] uuidToBytes(UUID uuid) { byte[] bytes = new byte[16]; ByteBuffer buffer = ByteBuffer.wrap(bytes); buffer.order(ByteOrder.LITTLE_ENDIAN); buffer.putInt((int) (uuid.getMostSignificantBits() >> 32)); buffer.putShort((short) (uuid.getMostSignificantBits() >> 16)); buffer.putShort((short) uuid.getMostSignificantBits()); buffer.order(ByteOrder.BIG_ENDIAN); buffer.putLong(uuid.getLeastSignificantBits()); return bytes; } }