thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ ll
total 4
-rw-r--r-- 1 thufir thufir 1319 2008-03-21 00:29 foo.jar
thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ java -jar foo.jar 
Exception in thread "main" java.lang.NoClassDefFoundError: com/
web_tomorrow/CPTest2/class
thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ jar -tf foo.jar 
META-INF/
META-INF/MANIFEST.MF
com/web_tomorrow/CPTest1.class
com/web_tomorrow/CPTest2.class
thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ jar -xf foo.jar 
thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ cat META-INF/MANIFEST.MF 
Manifest-Version: 1.0
Created-By: 1.6.0_03 (Sun Microsystems Inc.)
Main-Class: com.web_tomorrow.CPTest2.class

thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$ java com.web_tomorrow.CPTest2
Run CPTest2.main()
thufir@arrakis:~/java/build$ 
thufir@arrakis:~/java/build$