GPL license question.

I'm doing a project that I might want to try to sell or do something with later on. For the prototype, (will probably port to something more web friendly) i'm using Java with QT designer for the UI. Now my question is, if I use the open source license for QT, what kind of copyright issues will it cause? Will I only have to share the UI as open source or the whole system? Can potential competitors use my UI to provide the same product with their own system behind it? Any recommendations/java sucks comments?

>>8
Actually the QT designer automatically inserts the GPL virus in your software. The virus is impossible to remove and it's better to destroy the whole codebase if you ever wish to make profit by programming.