[java] JPanel vs JFrame in Java

I am learning Java gui. The way I learnt to create a window is to inherit or Extend JFrame class and it is good to use it, as JFrame contains all the properties of a Window. Now If I want to add something to this window, I need to use add() method. But Today I came across JPanel which also creates a windows and we can add stuff by jpanelObjec.add().

What is the difference between the two methods? Are they somehow related?

JFrame is the window; it can have one or more JPanel instances inside it. JPanel is not the window.

You need a Swing tutorial:

http://docs.oracle.com/javase/tutorial/uiswing/