What application do i use for java swing?

me and my Friend are gonna learn how to use some java stuff to make minecraft mods. but i cant figure something out. im on this part of the tut http://download.oracle.com/javase/tutorial/uiswing/start/compile.html and i realize im supposed to run the hello world. but what application? there is like 30 under bin in my java folder. what is it called? also im only 15 so make it simple im just learnign it lol.