title: Spring Data JPA repository throws null pointer
body: <p>I've been working with Spring Data with Spring Boot. With the JavaConfig documentation I have set up a Spring JPA configuration, but when calling the save method in my repository a null pointer is thrown. </p>
  
  <p>My repository:</p>
  
  <pre><code>import org.springframework.data.jpa.repository.JpaRepository;
  
  public interface HouseRepository extends JpaRepository&lt;House, Long&gt; {
  }
  </code></pre>
  
  <p>My POJO's:</p>
  
  <p>AbstractHouse</p>
  
  <pre><code>@MappedSuperclass
  @Table(name="houses")
  @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
  public abstract class AbstractHouse implements Serializable {
  
  @NotEmpty
  private String houseName;
  
  @NotEmpty
  private String houseNumber;
  </code></pre>
  
  <p>House</p>
  
  <pre><code>@Entity
  public class SmallHouse extends AbstractHouse {
  
  @Id
  @GeneratedValue
  private Long id;
  
  private Date created;
  
  private Date updated;
  </code></pre>
  
  <p>I've then got a service object that takes an Autowired repository and attempts to save using methods obtained through JPA:</p>
  
  <pre><code>@Service
  public class HouseService {
  
  @Autowired
  protected HouseRepository houseRepository;
  
  public void save(House house) {
      houseRepository.save(house);
  } 
  </code></pre>
  
  <p>My application class contains:</p>
  
  <pre><code>@SpringBootApplication
  @EnableScheduling
  @EnableJpaRepositories
  public class Application {
  
  public static void main(String[] args) throws Exception {
      SpringApplication.run(Application.class, args);
  }
  }
  </code></pre>
  
  <p>I am fairly new to Spring Data, so I do think its something within the configuration that I am missing, any advice would be greatly appreciated!</p>
  
  <p>--Update--</p>
  
  <p>Stack Trace:</p>
  
  <pre><code>java.lang.NullPointerException
      at com.jm.service.HouseService.save(HouseService.java:15)
      at com.jm.service.HouseClass.gatherHouses(HouseClass.java:43)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:497)
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:775)
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967)
      at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
      at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
      at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
      at java.lang.Thread.run(Thread.java:745)
  </code></pre>
  
  <p>And I call the method as such:</p>
  
  <pre><code>public class HouseMain {
  
      @Autowired
      public HouseService houseService;
  
      public void gatherHouse() {
      houseService = new HouseService();
      House h = new House();
      h.setHouseName("House1");
      h.setHouseNumber("12");
      try {
  
          HouseService.save(vmComp);          
          }
      } catch (Exception e) {
          e.printStackTrace();
      }
  }
  }
  </code></pre>
  
  <p>Then in my controller I am calling house.gatherHouse</p>