What is the correct way to use JPanels in Netbeans?

Question

I\'m new to Java GUI.

First I created a JFrame and have added a JPanel. After that I set it as a Null Layout. Then added a label and set a background image for the fram

Answer 1

I want to know whether it's correct or not to add 4 JPanels on a main JPanel?

Sure. Most of the Java GUIs you see that are any more than trivial put panels inside other panels.

Sometimes a different panel is used to group common controls or output components and possibly give them a titled border. More commonly different panels are used in order to use different layout managers in separate parts of the GUI. Here is a well known example that puts the details of the layout in a titled border for the panel..