I have a jar file that contains a package. I enter this command and it compiles:

javac -cp "C:\Program Files\Java\jdk1.5.0_05\bin\myPac.jar" app.java

but when I try to run the program by typing this command:

java -cp "C:\Program Files\Java\jdk1.5.0_05\bin\myPac.jar" app

It doesn't run and i get this exception error:

Exception in thread "main" java.lang.NoClassDefFoundError: app

Any ideas?