Adding 0's to string/int variable

Question

So I have been working on a naming convention which add 0\'s before a string. I\'m trying to do this the short handed way before breaking everything into if statements. Here

Answer 1

How about this?

("00000" + numberAsString).substring(numberAsString.length())

This will only work if you have 5 or less digit numbers.

Ideone link to check code

Reference

To be honest, I also think 4 times how this code works, but after understanding I posted as this is something out of the box.