Java threading problem, I think...?

before I ask my question, I want to note that I know having code is almost mandatory for any real help, but I want to refrain from adding code this time because it's a lot of code, and it is somewhat in an "in between" state. Moving on... I wrote a hangman game a few days ago, and it works fine on command line (or eclipse). However, I am currently working on a GUI for the game. The way the game works is it gets a user guess (a letter), and it checks if it's part of the word that has to be guessed. The issue I'm facing is, when I guess the first guess, the game runs fine, when I guess the second guess, the game runs fine, but after that, any more guesses don't get processed. However, when I run the game in debug mode, any number of guesses work fine, and the game runs fine. Moreover, the only thread that stops running when I encounter a breakpoint is main... is it possible that there's some sort of threading issue, and I should make main sleep?