Hey! These are some of the difference i studied a long back from googling the net. Correct me if i am wrong and add more if i missed out anything.
Java Thin Java runs only on the server.
Thick Java runs on client and server.
browser Thin Required.
Thick Optional. You can run the client portion as an Applet in the browser, or stand-alone without the browser. Getting rid of the browser gives you back RAM.
Speed Thin Slow. Everything must wait for the server to process and transmit the next screenful of information.
Thick Fast. Can instantly scroll especially if the app caches data locally. However, starting the application is slower than with thin client.
editing Thin Edits are done in block mode. You don't find out about your errors until you hit submit.
Thick You find out about an error the instant you key it, or sometimes as soon as you finish keying a field. The cursor is placed on the exact source of the error.
pizazz Thin You are limited to what you can pull off with HTML and animated gifs, or Javascript if you cheat on pure thin client.
Thick What the app does is limited only by your imagination. You have the full power of Java available

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hassle Thin You must do all your coding on a server. If you don't own a server, you will have a hard time espicially when you would like to debug.
Thick You do some of your coding on the server and some on the client. This makes more flexibility, also you can debug your client stand alone application.