Testing updated jar in project

I have a main java EE project in which I use multiple jar libraries.

For one of the specific jars, I am going into the original project of that jar, and updating its libraries, and re-importing the updated jar into the main project.

I am thinking of good ways to test that the updated jar still works in the application, so I decided upon looking for where the jar is being used. Is there a way in Eclipse to find every instance that the jar is being used (classes instantiated, methods called, etc)?

Should I just be looking for import statements or anything else?