This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
There is no difference between a jar file and a war file. It is just the extension but the utility (jar) does the same functionality of zipping the given files. The only difference being that only servlets and jsp pages are jar'red with a war extension. HTH
There are some requirements, though: there should be a directory called WEB-INF (capitals!!!) containing a file called web.xml (this is your deployment descriptor for servlets, etc). loose Java classes should go into WEB-INF/classes jarfiles go into WEB-INF/lib
I was never good at remembering dos-prompt commands. If you have J2EE Enterprise Edition, then its deployment tool will make a war file ... its a GUI, which allows you to choose files to be included in the WAR archive