JUnit

A unit testing framework for Java.

JUnit 4

Annotations

You can use annotations. Now there is no need to extend TestCase, instead you can annotate methods using the @Test annotation.

import org.junit.Test;

public class UrlLinkFilterTest {
    @Test
    public void testFilter() {
        // stub
    }
}

JUnit FAQ

The JUnit FAQ covers most questions you may have when using JUnit.