Here you can find the source of toBytes(long value, byte[] dest, int destPos)
public static void toBytes(long value, byte[] dest, int destPos)
//package com.java2s; public class Main { public static void toBytes(int value, byte[] dest, int destPos) { for (int i = 0; i < 4; i++) { dest[i + destPos] = (byte) (value >> ((7 - i) * 8)); }/* w ww.j av a 2s.com*/ } public static byte[] toBytes(int value) { byte[] dest = new byte[4]; toBytes(value, dest, 0); return dest; } public static void toBytes(long value, byte[] dest, int destPos) { for (int i = 0; i < 8; i++) { dest[i + destPos] = (byte) (value >> ((7 - i) * 8)); } } public static byte[] toBytes(long value) { byte[] dest = new byte[8]; toBytes(value, dest, 0); return dest; } public static byte[] toBytes(String digits, int radix) throws IllegalArgumentException, NumberFormatException { if (digits == null) { return null; } if (radix != 16 && radix != 10 && radix != 8) { throw new IllegalArgumentException("For input radix: \"" + radix + "\""); } int divLen = (radix == 16) ? 2 : 3; int length = digits.length(); if (length % divLen == 1) { throw new IllegalArgumentException("For input string: \"" + digits + "\""); } length = length / divLen; byte[] bytes = new byte[length]; for (int i = 0; i < length; i++) { int index = i * divLen; bytes[i] = (byte) (Short.parseShort( digits.substring(index, index + divLen), radix)); } return bytes; } }