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javajar

Multiple runnable classes inside JAR, how to run them?

I'm having problems with running multiple different classes from one JAR file. I know that I can set one of the classes inside JAR to by Main class that will be run after command java -jar myjar.jar, but what I want is something like: 

java -jar myjar.jar MyClass

Is it possible to do this that way, or do I have to create multiple JAR (each for one runnable class), or is it better to create 'manager' class that will run my other classes passing to them command line arguments?
I was looking for documentation or reference, but I couldn't find any.

Solution

  • The executable Jar file format only allows you to specify one main class. In order for you to be able to execute different applications, you'll need to either create a "manager" as you suggest, or to use the classpath instead:

    java -cp myjar.jar MyClass

    However, this approach will ignore the classpath you have configured in the Jar's manifest file.