softwarehangar7

public class HistoricalRecordController {

	public List<HistoricalRecord> listAll() {
		return Collections.EMPTY_LIST;
	}

}

softwarehangar7

public class HistoricalRecordControllerTest {

	@Test
	public void testRetrieveEmptyList() throws Exception {
		final HistoricalRecordController recordController = new HistoricalRecordController();
		final List<HistoricalRecord> historicalRecords = recordController.listAll();
		assertEquals(0, historicalRecords.size());
	}
}

softwarehangar7

public abstract class HistoricalRecord {
  //bunch of properties here
}

public class ProductHistoricalRecord extends HistoricalRecord {
  //bunch of properties here
}

public class ServiceHistoricalRecord extends HistoricalRecord{
  //bunch of properties here