Swing is a light weight component whereas Applet is a heavy 
weight Component..Applet Does not require main 
method ,instead it needs init method.

Swing is a set of classes under JFC that provide 
lightweight visual component , enable creation of 
attractive GUI. But Applet is heavyweight component and 
needs web browser or tool known as AppletViewer.

Applet have no main method, but swing have.

swing is a light wight component.

Component
Swing :Swing is light weght Component
Applet : Applet is heavy weight Components

Look and feel 
Swing: Using UIManager swing have look and feel according 
to user view u can change look and feel 
Applet: Applet Does not provide this facility 

Compile 
Swing : swing uses for stand lone Applications ,Swing 
have   main method to execute the program
Applet : Applet need HTML code for Run the Applet 

Swing : uses MVC Model view Controller 
Applet : not 

Swing : swing have its own Layout ..like most popular Box 
Layout
Applet : Applet uses Awt Layouts..like flowlayout

Thread 
Swing :Swing have some Thread rules 
Applet :There is no any rule

Swing : heavy weight
Applet : light weight

Apple :to execute Applet programe we should need any one 
browser like Appletviewer,web browser.
Because Applet using browser container to run and all 
action control with in browser container

swing :to execute swing no need any browser By which we can 
create stand alone application
But Here we have to add container and maintain all action 
control with in frame container


Applet : we dependent on brower to execute and action


swing : own 

simply Instance problem

applet: the components of applet are from underlying 
operating system .
swing : Swing creates its own component.