java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.reflect.ParameterizedType

[tryuefang]

I am using below version info:

org.jsondoc
jsondoc-core
1.2.17

	<dependency>
		<groupId>org.jsondoc</groupId>
		<artifactId>jsondoc-springmvc</artifactId>
		<version>1.2.17</version>
	</dependency>

	<dependency>
		<groupId>org.jsondoc</groupId>
		<artifactId>jsondoc-ui</artifactId>
		<version>1.2.17</version>
	</dependency>

when I run it with above version, it shows me below error:
java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.reflect.ParameterizedType
at org.jsondoc.springmvc.scanner.AbstractSpringJSONDocScanner.buildJSONDocObjectsCandidates(AbstractSpringJSONDocScanner.java:112)
at org.jsondoc.springmvc.scanner.AbstractSpringJSONDocScanner.appendSubCandidates(AbstractSpringJSONDocScanner.java:168)
at org.jsondoc.springmvc.scanner.AbstractSpringJSONDocScanner.jsondocObjects(AbstractSpringJSONDocScanner.java:200)
at org.jsondoc.core.scanner.AbstractJSONDocScanner.getJSONDoc(AbstractJSONDocScanner.java:96)
at org.jsondoc.springmvc.controller.JSONDocController.getApi(JSONDocController.java:70)
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:498)
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:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
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:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:958)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:452)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1087)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
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)

[ST-DDT]

I have the same issue, AFAICT this is caused by generic types.

[ST-DDT]

The solution to this bug is adding

if (parametrizedType instanceof Class) {
	candidates.add((Class<?>) parametrizedType);
} else if (parametrizedType instanceof WildcardType) {
	candidates.add(Void.class);
// NEWLY ADDED - START
} else if (parametrizedType instanceof TypeVariable) {
	// Copied from a few lines down
	candidates.add(Void.class);
	candidates.addAll(buildJSONDocObjectsCandidates(candidates, (Class<?>) ((ParameterizedType) type).getRawType(), parametrizedType, reflections));
	// This might be useful for the below block as well
	for (Type bound : ((TypeVariable<?>) parametrizedType).getBounds()) {
		if (bound instanceof Class) {
			candidates.add((Class<?>) bound);
		}
	}
// NEWLY ADDED - END
} else {
	candidates.addAll(buildJSONDocObjectsCandidates(candidates, (Class<?>) ((ParameterizedType) parametrizedType).getRawType(), parametrizedType, reflections));
}

to AbstractSpringJSONDocScanner:112

Refactoring these might be useful to avoid code duplication.
Remove the specialization for Map and Collection and just iterate over all type parameters and not just the first as you currently do