import java.math.BigInteger; public class Main { public static void main(String[] argv) throws Exception { byte[] bytes = new byte[] { (byte) 0x12, (byte) 0x0F, (byte) 0xF0 }; BigInteger bi = new BigInteger(bytes); // Format to hexadecimal String s = bi.toString(16); if (s.length() % 2 != 0) { s = "0" + s; } } }