Multipart file upload using Postman and Spring : Object is not an instance of declaring class - spring

Question

Situation: I'm making a POST request to a Spring controller using Postman. There is a text JSON, and a Multipart file.
Problem: I get an error as follows:
Method [public java.lang.String com.dure.ivizard.core.datamanagement.export.controller.FileUploadAction.uploadFileHandler(org.springframework.web.multipart.MultipartFile,javax.servlet.http.HttpSession,java.lang.String)]
Resolved arguments:
[0] [type=org.springframework.web.multipart.commons.CommonsMultipartFile] [value=org.springframework.web.multipart.commons.CommonsMultipartFile#e421749]
[1] [type=org.apache.catalina.session.StandardSessionFacade] [value=org.apache.catalina.session.StandardSessionFacade#725e9373]
[2] [type=java.lang.String] [value={
"userid":"1",
"email":"admin#gmail.com"
}]
] with root cause
java.lang.IllegalArgumentException: object is not an instance of declaring class
The input parameters are as follows:
Key: inputdataJsonStr
Type: String
Value: {"userid" : "1", "email" :"abc#gmail.com"
Key: file
Type: File
Value:
Here is the Spring controller's declaration:
#SuppressWarnings("rawtypes")
#Transactional
#RequestMapping(value = "/confirmUploadLocalAttrFile_new", method = RequestMethod.POST)
public #ResponseBody
String uploadConfirmLocalAttrHandler_new(#RequestParam("file") MultipartFile file, HttpSession session, #RequestParam String inputdataJsonStr){
Full stack trace is as follows:
2018-01-08 12:27:35 INFO DureContextListenerImpl:85 - ********************Application conext set
2018-01-08 12:27:35 INFO SimpleCORSFilter:24 - SimpleCORSFilter init
2018-01-08 12:27:35 INFO DispatcherServlet:473 - FrameworkServlet 'spring': initialization completed in 4026 ms
Jan 08, 2018 12:27:35 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [spring] in context with path [/ivizard] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: object is not an instance of declaring class
HandlerMethod details:
Controller [com.sun.proxy.$Proxy48]
Method [public java.lang.String com.dure.ivizard.core.datamanagement.export.controller.FileUploadAction.uploadConfirmLocalAttrHandler_new(org.springframework.web.multipart.MultipartFile,java.lang.String,javax.servlet.http.HttpSession)]
Resolved arguments:
[0] [type=org.springframework.web.multipart.commons.CommonsMultipartFile] [value=org.springframework.web.multipart.commons.CommonsMultipartFile#b32dcc0]
[1] [type=java.lang.String] [value={
"dataformat":"1",
"userid":"1",
"datacategory": "2",
"countryid":"0",
"targetOrIndicatorId":"21",
"email":"admin#gmail.com"
}]
[2] [type=org.apache.catalina.session.StandardSessionFacade] [value=org.apache.catalina.session.StandardSessionFacade#67577440]
] with root cause
java.lang.IllegalArgumentException: object is not an instance of declaring class
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.invoke(InvocableHandlerMethod.java:219)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
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:88)
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:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
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:962)
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$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
What's puzzling is that even simple POST requests with just a JSON parameter have stopped working, and give the same error.

Answer 1

#SuppressWarnings("rawtypes")
#Transactional
#RequestMapping(value = "/confirmUploadLocalAttrFile_new", method =
RequestMethod.POST)
public #ResponseBody
String uploadConfirmLocalAttrHandler_new(#RequestParam("file") MultipartFile
file, HttpSession session, #RequestParam("jsonStr") String inputdataJsonStr){

Answer 2

It worked by simply copying the controller and the entire function as it was to another file.
How did it work ? Why did it work ? These questions will be answered by God when we go to Heaven.