Start Java main in another process (VM)

I have a server client project and for testing purposes I want to start the server in a whole new process. The problem is, I have just a main() method in project, no jar. So my guess would be something like

Runtime.getRuntime().exec("javac MyServer.java");
Runtime.getRuntime().exec("java class MyServer");

But I am really not sure about it and also I don't exactly like the need to start javac for each test case.

How should I proceed?

EDIT

I want to start the process in the @Before method and destroy it in @After. It has to run automatically, so manual turning on the server is not an option. What I was looking for is a way to eliminate compilation of the server class. But now I guess there is no other way.

Take a look at JUnit, what I think you want to do is run a series of tests against your client, with a server running. You can accomplish this by writing a JUnit test which makes use of the @Before annotation to run a setup method before each test. For example:

import org.junit.Before

public class TestClient {
    private static final int port = 20000 + new Random().nextInt(10000);
    private MyServer server;

    @Before
    public void setup() {
        // setup server
        server = new MyServer(port);
        server.start();
    }

    @Test
    public void testX() {
        // test x
    }

    @Test
    public void testY() {
        // test y
    }
}