Why should I use a Game-Engine like lwjgl or libgdx instead of Swing?

Hey Guys,

I’m new in the game delevopment with java. And now I want to learn more about Game Engines.
Until now, I only heard of Swing. Than I found out, that there are more game engines like lwjgl, libgdx, etc.

Now my problem:
Why should I use lwjgl or something like this? What makes it “better” (better is a bad word for it I think).
And whats the difference about lwjgl / libgdx? Where are the pros and cons?

Hope you can help me there. Please don’t link me to the homepages of the Engines… Yes, there are informations about it… But only generally information, but I want to get a little deeper.
Thanks for help!!

greetz…