Java tutorial
//package com.java2s; public class Main { static int hexCharToInt(char c) { if (c >= '0' && c <= '9') return (c - '0'); if (c >= 'A' && c <= 'F') return (c - 'A' + 10); if (c >= 'a' && c <= 'f') return (c - 'a' + 10); throw new RuntimeException("invalid hex char '" + c + "'"); } }