Intellij IDEA how to run a class not the entire project?

Question

is there a way to run (not only compile) a single class (with a main method) instead to run the entire project as does Intellij IDEA?

And, is it possible to open different projects in the same window instead to opening them in a new window or in place of the current project?

Answer 1

You can only have 1 project per window. However, you can load multiple modules into 1 project. Each module can have it's own compiler, language, or any other set up.

If you right click inside the main method of your class, you should have an option to "create MyClass run/debug" or an option to just run it without creating a launch config.