Running classes from Java GUI

I've recently decided to start a project of my own.

What I aim to do is to run Test XML files from a Java GUI.

In general terms, is it possible to run a java class from a separate Java class ( which will be my GUI ) that are in different projects?

In my GUI the aim is that the user will be able to give the path to the XML file, from there they can then press a run button which will then execute the code.

I know I've mentioned my aim is to run XML files but just for a more generalized question that may be useful to more people I presume the same theology would be the same for running a Java class.

Is something like this possible?