请教一个JpaRepository的问题

// repository

public interface EmployeeJpaRepo extends JpaRepository<Employee,Integer> {
}

// EmployeeJpaRepoTest
public class EmployeeJpaRepoTest {

    private ApplicationContext ctx = null;

    private EmployeeJpaRepo employeeJpaRepo = null;

    @Before
    public void setUp(){
        ctx = new ClassPathXmlApplicationContext("bean-new.xml");
        employeeJpaRepo = ctx.getBean(EmployeeJpaRepo.class);
        System.out.println(" setup is running..... ");
    }

    @After
    public void close(){
        ctx = null;
        System.out.println(" close is running..... ");
    }

    @Test
    public void findOne(){
        Employee employee = employeeJpaRepo.findOne(10);
        System.out.println(employee);        
       
        //这个方法在JpaRepository接口中有出现，我开始觉得会返回一个Employee对象，结果看返回值是一个抽象类
        //那么这个geOne方法放在类里面主要做什么用，该怎么用
        employeeJpaRepo.getOne(11);       
        
        System.out.println("id102是否存在"+employeeJpaRepo.exists(102));
    }

}