Spring 4 - Autowire Generic - spring

Question

I create an generic interface CRUDService to generate multiple entity service classes with all implement the same CRUD Methods.
interface CRUDService<T> {
public abstract T saveEntity(T entity)
public abstract T getEntity(T entity)
public abstract long getCount()
}
Then I implemented from my entity Hypervisor an service class HypervisorService which implements my CRUDService
#Service
class HypervisorService implements CRUDService<Hypervisor> {
#Autowired
private HypervisorRepository hypervisorRepository
#Override
#Transactional
public Hypervisor saveEntity(Hypervisor entity) {
return hypervisorRepository.saveAndFlush(entity)
}
#Override
public Hypervisor getEntity(Hypervisor entity) {
return hypervisorRepository.findOne(entity.getId())
}
#Override
public long getCount() {
return hypervisorRepository.count()
}
}
But when i try to autowire it with
#Autowired
private CRUDService<Hypervisor> hypervisorService
I got an "java.lang.ClassCastException: com.sun.proxy.$Proxy68 cannot be cast to net.ifis.ites.hermes.services.HypervisorService" exception.
I don't understand why Spring sayes it has an classcastexception but when i changed my Service code to
#Service
class HypervisorService<Hypervisor> implements CRUDService<Hypervisor> {
...
}
My code works and i can use my generic interface but i don't think this is a good practice to use it.
Stack Trace :
java.lang.ClassCastException: com.sun.proxy.$Proxy68 cannot be cast to net.ifis.ites.hermes.services.HypervisorService
at net.ifis.ites.hermes.services.HypervisorService$saveEntity.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:110)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:122)
at net.ifis.ites.hermes.ui.MyVaadinUI.init(MyVaadinUI.groovy:38)
at com.vaadin.ui.UI.doInit(UI.java:646)
at net.ifis.ites.hermes.ui.MyVaadinUI.doInit(MyVaadinUI.groovy)
at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:214)
at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74)
at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
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.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:358)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:128)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:146)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
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:966)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
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:219)
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:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1521)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1478)
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)
In my VaadinUI i autowire only my service class and generate an hypervisor and try to save it to my database and visualize the current database counts from all hypervisors as an label.
#Component
#SpringUI
class MyVaadinUI extends UI {
#Autowired
private CRUDService<Hypervisor> hypervisorService
#Override
protected void init(VaadinRequest vaadinRequest) {
VerticalLayout layout = new VerticalLayout()
Hypervisor hypervisor = hypervisorService.saveEntity(new Hypervisor("KVM"))
layout.addComponent(new Label("Hypervisors : " + hypervisorService.getCount()))
setContent(layout)
}
}
I will try to use CGLIB for my application now.

Answer 1

I use in my configuration
#EnableAspectJAutoProxy(proxyTargetClass=true) and now my code works with
class HypervisorService implements CRUDService<Hypervisor> {
...
}