Selecting main class in a runnable jar at runtime

java jar executable-jar
Tomasz picture Tomasz · Jan 7, 2010 · Viewed 47.7k times · Source

I have two main classes in the app. When I package it to a runnable jar (using Eclipse export function) I have to select a default main class.

Is there a way to access the non-default main class from the jar at runtime?

Answer

Jeremy Raymond picture Jeremy Raymond · Jan 7, 2010

You can access both via java -cp myapp.jar com.example.Main1 and java -cp myapp.jar com.example.Main2. The default main class in the jar is for when you invoke your app via java -jar myapp.jar.

See JAR_(file_format) for more details. When you select the main class in Eclipse this is what gets set in: Main-Class: myPrograms.MyClass inside of the jar manifest META-INF/MANIFEST.MF in side of the jar file.

Related questions

Running JAR file on Windows

I have a JAR file named helloworld.jar. In order to run it, I'm executing the following command in a command-line window: java -jar helloworld.jar This works fine, but how do I execute it with double-click instead? Do I …

Read More
What causes "Unable to access jarfile" error?

I want to execute my program without using an IDE. I've created a jar file and an exectuable jar file. When I double click the exe jar file, nothing happens, and when I try to use the command in cmd …

Read More
How to get the path of a running JAR file?

My code runs inside a JAR file, say foo.jar, and I need to know, in the code, in which folder the running foo.jar is. So, if foo.jar is in C:\FOO\, I want to get that path …

Read More