A common programming solution is to use threads

A common programming solution is to use threads. But then, two ‘llyou hav erpoblesm.

I don't think that this joke could be told by a real person. You pretty much have to  type it out. This is a programming joke. The humor lies in the fact that the person that is reading the joke tries to parse the last part of the sentence, and then realizes that it is a jumbled version of the words "You'll have two problems"

The reason why this is funny is that threads can introduce a type of bug known as a race condition, which can cause things to happen in the wrong order. The reader is supposed to assume that that happened here, specifically that a race condition caused the letters of the joke to be printed to the screen in the wrong order.