I have a swing based application in a package called moiveJava2. My moment interval class, WindowGUIMI, has one main method which instantiates the rest of the application from another class called WindowGUI. I have created a manifest file called MovieJava2.MF which has one line equal to: Main-Class: WindowGUIMI //plus a carriage return My dos command lines thus far have been: C:\java_programs\MovieJava>jar cvf MovieJava2.jar movieJava2\* C:\java_programs\MovieJava>jar cmf MovieJava2.MF MovieJava2.jar movieJava2\*.class When I double click on the jar file I get a JVM Launcher error dialog which says: "Could not find the main class. Program will exit". What have I done wrong here?