"java.lang.IllegalArgumentException: Projection type must be an interface" Error

Question

I am having difficulty in implementing projection in Spring Data JPA:

2017-10-19 11:31:33.968 ERROR 4272 --- [nio-8080-exec-6] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessApiUsageException: Projection type must be an interface!; nested exception is java.lang.IllegalArgumentException: Projection type must be an interface!] with root cause

java.lang.IllegalArgumentException: Projection type must be an interface!
    at org.springframework.util.Assert.isTrue(Assert.java:92) ~[spring-core-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.data.projection.ProxyProjectionFactory.createProjection(ProxyProjectionFactory.java:110) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.data.projection.SpelAwareProxyProjectionFactory.createProjection(SpelAwareProxyProjectionFactory.java:42) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at th.co.geniustree.springdata.jpa.repository.support.JpaSpecificationExecutorWithProjectionImpl.lambda$readPageWithProjection$1(JpaSpecificationExecutorWithProjectionImpl.java:77) ~[specification-with-projections-1.0.5.jar:1.0.5]
    at org.springframework.data.domain.Chunk.getConvertedContent(Chunk.java:168) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.data.domain.PageImpl.map(PageImpl.java:104) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at th.co.geniustree.springdata.jpa.repository.support.JpaSpecificationExecutorWithProjectionImpl.readPageWithProjection(JpaSpecificationExecutorWithProjectionImpl.java:77) ~[specification-with-projections-1.0.5.jar:1.0.5]
    at th.co.geniustree.springdata.jpa.repository.support.JpaSpecificationExecutorWithProjectionImpl.findAll(JpaSpecificationExecutorWithProjectionImpl.java:49) ~[specification-with-projections-1.0.5.jar:1.0.5]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_131]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_131]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_131]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_131]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:504) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:489) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:461) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:56) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282) ~[spring-tx-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) ~[spring-data-jpa-1.11.7.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) ~[spring-data-commons-1.13.7.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at com.sun.proxy.$Proxy90.findAll(Unknown Source) ~[na:na]
    at com.lbs.data.demo.topic.TopicService.getAllSimpleTopics(TopicService.java:68) ~[classes/:na]
    at com.lbs.data.demo.topic.TopicController.getAllSimpleTopics(TopicController.java:23) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_131]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_131]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_131]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_131]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1457) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_131]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_131]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.20.jar:8.5.20]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]

My projection class is:

@Projection(name="topicSimple", types = Topic.class)
public interface TopicSimpleOuter {
        String getId();
        String getName();
}

My entity class is:

@Entity
@ProjectionWithSpecification (interfaceClass = "com.lbs.data.demo.topic.TopicRepository.TopicSimple")
public class Topic {
...
}

My Repo class is:

@Repository
@RepositoryRestResource(excerptProjection = TopicSimpleOuter.class)
public interface TopicRepository extends JpaRepository<Topic,String>,JpaSpecificationExecutorWithProjection<Topic> {//interface olması ne kadar ilginç

    List<TopicSimpleOuter> findById(String id);

}

Configuration class is:

public class TopicConfiguration extends RepositoryRestConfigurerAdapter {

    @Override
    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        config.getProjectionConfiguration().addProjection(TopicSimpleOuter.class);
    }
}

and related controller method is like this:

@RequestMapping(value = "/topicsSimple/{id}/projection=topicSimple", method = RequestMethod.GET)
    public Page<TopicSimpleOuter> getAllSimpleTopics(@PathVariable String id){
        return topicService.getAllSimpleTopics(id);
    }

Although I had properly added projections it is still complaining about the type of the projection.

Besides when I write a test class and use it there is no problem, however when I use postman I receive the above error. What am I missing?

Player One · Answer 1 · 2019-01-15T08:22:58.103

23

I had this error when the return type of a get method in my interface did not match the type in my entity.

For this case I'd guess that String getId(); does not match the type of id on the entity itself (although all the code posted has String as the type for the ID, the code of the entity itself is missing, and if the issue is the same as mine was then that's the bit that needs to match).

edited Jan 15 '19 at 08:22

answered Dec 27 '18 at 22:43

Player One

607
6
12

I had ZonedDateTime and was Date – Inês Gomes May 25 '20 at 15:23

score 7 · Answer 2 · answered Jun 06 '18 at 07:33

I had the same Exception thrown in one of my unit tests after upgrading Spring Boot from 1.4.1 to 1.5.13

It looks like the newer version is stricter in terms of the ordering of the getters in my Projection interface. I have a "SELECT" statement in my Repository that returns a List of Projection and the fix was to make sure that my Projection interface has the same orderings in its getter methods as the ones in "SELECT" statement.

I wonder if the cause of your issue is similar to mine.

score 2 · Answer 3 · answered Jul 07 '20 at 02:55

2

I had this error when the return type of a get method in my interface did not match the type of data. This should be int,but I used boolean

answered Jul 07 '20 at 02:55

g3c2

21
2

1

Please add a one-liner fix to OPs code. Your answer seems a bit incomplete – shuberman Jul 07 '20 at 03:17
My error code: boolean getEnabled(); I modify it to : int getEnabled(); THe filed enabled in db is type:int, length:1. – g3c2 Jul 23 '20 at 08:51

score 2 · Answer 4 · answered Oct 28 '20 at 10:46

I had the same problem while returning a JSON type in projection. Although I was using 'hibernate-types-52' from Vlad Mihalcea and my field was like Map<String, Translation> translations;, I needed to create ITranslation interface that exactly matches Translation class and replace it in map: Map<String, ITranslation> translations; which solved my issue.

Also, if projection contains another entity object, the solution could be also to replace it with the interface.

"java.lang.IllegalArgumentException: Projection type must be an interface" Error

4 Answers4

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