What does look and feel (java swing) mean?

Actually what is meant by look and feel?

What is the meaning of Java Swing?

What Does Java Swing Mean? Java Swing is a lightweight Java graphical user interface (GUI) widget toolkit that includes a rich set of widgets. It is part of the Java Foundation Classes (JFC) and includes several packages for developing rich desktop applications in Java.

What is meant by pluggable look and feel in Java?

Pluggable look and feel is a mechanism used in the Java Swing widget toolkit allowing to change the look and feel of the graphical user interface at runtime.

It means how the Graphical User Interface (GUI) looks like and behaves. Every OS has its own typical Look&Feel.

At the beginning, Java had its own, but of course most people want to have their applications look like the others of their OS.

You can change the L&F of your Java applications, read about it in the tutorials.

Read about L&F in general at Wikipedia.