Can you tell on runtime if you're running java from within a jar?

Question

I have an application that some of my users run from Eclipse, and others run it by using a jar file.

I want some actions to be done when running from within the jar,

Answer 1

Another approach is putting information in the manifest file, and testing for if that information is available at runtime.

If it is, then the code was started with "-jar". Otherwise it was started in another way, e.g. directly from Eclipse.