Edit: It looks like I'm going to start porting my C++/ObjC++ code to FP, so I'll be around for a while. When I have a spare hour, I'll start on a basic Form to see how it all works. It looks like Java Swing/Matisse to me. Is it kind of the same idea?
Not the same idea, not the same principle, not the same design, certainly not the same implementation.
LCL has more balanced OO-event driven approach, while Swing is all OOP (you don't assign event handlers in Swing, you create a class instance implementing interfaces describing the events instead).
LCL strives to be as native as possible to the chosen widgetset, Swing takes a unified look approach (more like fpGUI).
LCL is modeled after VCL 6, Swing is original design from Sun based on their earlier AWT (now this one is much closer to LCL's native approach).