How to sequentially execute 2 Java classes via mvn command

Question

I have 2 Java classes which have a symbiotic relationship.

Class 1 produces some output files and Class 2 consumes the output of class 1 and validates it. Both of these

Answer 1

Execute the main() method of your class under test from within a JUnit method.

public class Class2 {
  @Before
  public void produceOutputFiles() {
      Class1.main(new String[] { "these", "are", "commandline", "arguments"});
  }

  @Test
  public void validateClass1Output() {
      //read in the files and validate the output
  }
}

Invoking Class1 via Process.exec() is an option with many downsides. It is much simpler to keep both the test and the tested code within the same JVM.