Junit before class ( non static )

If you don't want to set up static initializers for one time initialization and are not particular about using JUnit, take a look at TestNG. TestNG supports non-static, one-time initialization with a variety of configuration options, all using annotations.

In TestNG, this would be equivalent to:

@org.testng.annotations.BeforeClass
public void setUpOnce() {
   // One time initialization.
}

For teardown,

@org.testng.annotations.AfterClass
public void tearDownOnce() {
   // One time tear down.
}

For the TestNG equivalent of JUnit 4's @Before and @After, you can use @BeforeMethod and @AfterMethod respectively.

To use an empty constructor is the easiest solution. You can still override the constructor in the extended class.

But it's not optimal with all the inheritance. That's why JUnit 4 uses annotations instead.

Another option is to create a helper method in a factory/util class and let that method do the work.

If you're using Spring, you should consider using the @TestExecutionListeners annotation. Something like this test:

@RunWith(SpringJUnit4ClassRunner.class)
@TestExecutionListeners({CustomTestExecutionListener.class, 
     DependencyInjectionTestExecutionListener.class})
@ContextConfiguration("test-config.xml")
public class DemoTest {

Spring's AbstractTestExecutionListener contains for example this empty method that you can override:

public void beforeTestClass(TestContext testContext) throws Exception {
    /* no-op */
}

NOTE: DO NOT overlook/miss DependencyInjectionTestExecutionListener while adding custom TestExecutionListeners. If you do, all the autowires will be null.

A simple if statement seems to work pretty well too:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:test-context.xml"})
public class myTest {

    public static boolean dbInit = false;

    @Autowired
    DbUtils dbUtils;

    @Before
    public void setUp(){

        if(!dbInit){

            dbUtils.dropTables();
            dbUtils.createTables();
            dbInit = true;

        }
    }

 ...