Unable to select launch configuration when exporting Scala from Eclipse as JAR

I have a Scala project in Eclipse and I want to export it as a Jar file so I can deploy it elsewhere. I can run it in Eclipse without error.

Problem:

I right click on my project and select Export - Java - Runnable JAR file. I have to select a launch configuration, but the launch configuration menu is empty.

What I have tried:

• I read this thread "Run configuration" Shows empty when trying to export Runnable Jar?

I was prompted to run my main method to create a launch config. However, I have run it many times already.

2. I tried to export it as a regular JAR. However, then the main part of the method selection is empty. This is probably due to the same problem.

3. I read in some thread that this can cause problems if I have two main methods. I commented on another one and I still have a problem.

4. I tried to clean up the project.

Additional Information:

- I added scala -swing and scala -parser-combinators to the referenced libraries

-This is a screenshot of my file:

There is a small yellow warning triangle. But there is no text on it. Edit: I found out that I can test it in the Problems tab. It says there are two fail warnings.

Choosing the scala -swing and scala -parser combinations removed the warning triangle, but did not solve the problem. Initially only the src folder was selected. I also tried to select all of them.