Java: convert byte[] to base36 String

Try using BigInteger:

String hash = "43A718774C572BD8A25ADBEB1BFCD5C0256AE11CECF9F9C3F925D0E52BEAF89";
//use a radix of 16, default would be 10 
String base36 = new BigInteger( hash, 16 ).toString( 36 ).toUpperCase();

This might work:

BigInteger big = new BigInteger(your_byte_array_to_hex_string, 16);

big.toString(36);