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wrong classLoader usage

See original GitHub issue

Hello,

we are using JMapper 1.6.1.CR1 in a Spring Boot Environment. We have a controller with a method like this:

public List<CampaignGroupDTO> getByClientId(@RequestParam final long clientId, @RequestParam final boolean withCampaigns) {
                JMapper<CampaignGroupDTO, CampaignGroup> mapper = new JMapper<>(CampaignGroupDTO.class, CampaignGroup.class);
		List<CampaignGroupDTO> dtos = new ArrayList<>();
		this.campaignGroupService.findAllWithCampaigns(clientId).forEach(c -> dtos.add(mapper.getDestination(c)));
		return dtos;
	}

Calling getByClientId() the first time works fine, and also the mapping does what we expect it should. But calling the method twice raises following exception:

com.googlecode.jmapper.exceptions.JMapperException: javassist.CannotCompileException: by java.lang.LinkageError: loader (instance of org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedWebappClassLoader): attempted duplicate class definition for name: “demycompanycampaigngroupdtoCampaignGroupDTOdemycompanycampaigngroupentityCampaignGroup” at com.googlecode.jmapper.config.JmapperLog.ERROR(JmapperLog.java:46) at com.googlecode.jmapper.JMapper.<init>(JMapper.java:437) at com.googlecode.jmapper.JMapper.<init>(JMapper.java:373) at com.googlecode.jmapper.JMapper.<init>(JMapper.java:360) at de.mycompany.campaigngroup.controller.CampaignGroupController.getByClientId(CampaignGroupController.java:116) 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:483) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:208) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:89) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) 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:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) 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) Caused by: javassist.CannotCompileException: by java.lang.LinkageError: loader (instance of org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedWebappClassLoader): attempted duplicate class definition for name: “demycompanycampaigngroupdtoCampaignGroupDTOdemycompanycampaigngroupentityCampaignGroup” at javassist.ClassPool.toClass(ClassPool.java:1170) at javassist.ClassPool.toClass(ClassPool.java:1113) at javassist.ClassPool.toClass(ClassPool.java:1071) at javassist.CtClass.toClass(CtClass.java:1264) at com.googlecode.jmapper.generation.JavassistGenerator.generate(JavassistGenerator.java:90) at com.googlecode.jmapper.generation.MapperGenerator.generateMapperClass(MapperGenerator.java:74) at com.googlecode.jmapper.generation.MapperBuilder.generate(MapperBuilder.java:88) at com.googlecode.jmapper.JMapper.createMapper(JMapper.java:450) at com.googlecode.jmapper.JMapper.<init>(JMapper.java:432) … 63 more Caused by: java.lang.LinkageError: loader (instance of org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedWebappClassLoader): attempted duplicate class definition for name: “demycompanycampaigngroupdtoCampaignGroupDTOdemycompanycampaigngroupentityCampaignGroup” at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:760) at java.lang.ClassLoader.defineClass(ClassLoader.java:642) 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:483) at javassist.ClassPool.toClass2(ClassPool.java:1183) at javassist.ClassPool.toClass(ClassPool.java:1164)

Any help would be appreciated 😃

Jan