NumberFormatException error (parseInt)

Question

Hopefully a very simple query, but it\'s left me scratching my head.

I have a string, which is just a single integer, and I\'m trying to then get that integer out as

Answer 1

If the string is really 1, the exception can't happen. So I would say the string is not actually 1.

do a data.toCharArray() and print each character's code (cast to int). It may turn out that there is a hidden character before the digit, for example. (edit: it appears iluxa mentioned this option in a comment while I was writing the answer)

Try data = data.trim() before passing it to parseInt(..)

Answer 2

Note that DatagramPackate.getData() returns the whole buffer!

The data you received is only a part of it:

The data received or the data to be sent starts from the offset in the buffer, and runs for length long.

So to convert the data to a String you should use this constructor:

String message = new String(pac.getData(), pac.getOffset(), pac.getLength(), "UTF-8");

Note that I specify the UTF-8 encoding here, as not specifying an encoding would result in the platform default encoding to be used, which is generally not what you want.