Java 7, JSP, Spring 3, Apache-Tomcat 7.0.63. Netbeans.
I made changes to an existing JSP file, and changed the backing form object. I went through the JSP to ensure that all references were backed by a field of the correct name in the backing form object.
In the controller, I have a private saveEditedOrNewItem(); it invokes a method to initialize variables in the model for the page - setCommonModelAttributesForEdit(). The program bombs when the former calls the latter, throwing a NullPointerException, but I'm not dereferencing anything, I am making no calls within the call to get parameters or anything. One of the parameters is null, but that would not cause NPE by itself.
I have a breakpoint on the first executable line of setCommonModelAttributesForEdit(); that breakpoint is not reached when the error is triggered (though it executes on a previous invocation and runs to completion without error, so that method is executable).
Here's the code that throws the error:
if (errors.hasErrors()) {
if (entityCode == null || entityCode.equals("")) { entityCode = "Select"; }
Integer entityId = prospectForm.getentityId();
String prospectName = prospectForm.getName();
Object leafNodeFlag = getLeafNodeFlag(request);
Boolean bLeafNodeFlag = (Boolean)leafNodeFlag;
boolean bbLeafNodeFlag = (boolean)bLeafNodeFlag;
Integer logoAttachmentId = prospectForm.getLogoAttachmentId();
ModelMap localModelMap = model;
// the following is line 474 in the stacktrace
setCommonModelAttributesForEdit(localModelMap, entityCode, entityId,
prospectName, bbLeafNodeFlag, prospectForm,
logoAttachmentId);
return prospectEditView;
And here's the error stacktrace:
java.lang.NullPointerException
at com.accesspointinc.crm.prospect.MyFormController.saveEditedOrNewProspect(MyFormController.java:474)
at com.accesspointinc.crm.prospect.MyFormController.saveNewProspect(MyFormController.java:434)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
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 com.accesspointinc.commons.filter.SessionTimeoutCookieFilter.doFilter(SessionTimeoutCookieFilter.java:40)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.accesspointinc.commons.filter.StatesFilter.doFilter(StatesFilter.java:34)
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:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:614)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:322)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2516)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2505)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:722)
I 'flattened' all the parameters passed to setCommonModelAttributesForEdit(); I have a breakpoint on the call, and can examine all the values being passed in. I even ensured I wouldn't have to cast within the method call. The logoAttachmentId is null, the rest have non-null values. To repeat, a breakpoint set at the start of setCommonModelAttributesForEdit() is not hit on this invocation, though it is hit on an earlier invocation.
If I do "step into" instead of "step over" for the call, I end up in an InvocationTargetException constructor with a target of NullPointerException; the call stack indicates (eventually) that I am in a call from SessionTimeoutCookieFilter.doFilter(); the class is an extension of GenericFilterBean, and the line where it is failing is filterChain.doFilter(request, response);
So it is not your mothers NullPointerException. I am not dereferencing anything in my code, and it halts when I attempt to call a private method within a class in which I'm already executing, so the object for which the method is being referenced is already instantiated. Neither of these are static methods. I have done "clean and compile" multiple times, I have restarted NetBeans, I have rebooted Windows, I have cleaned my browser's cache.
Can anyone suggest what else I might do to find this problem?
Edit: I don't think this qualifies as a duplicate of the question for which it has been closed as a duplicate. Just because a question involves a null pointer does not mean it is a duplicate of the Big "Null Pointer" question.
The cause of this NPE (autobox conversion) was mentioned once in its supposed duplicate, in a comment, and in a different context than it occurred in this question. The current question turned out to be answered by autoboxing as part of parameter passing to a method call; the only mention of it in the Big Question was in an assignment statement. I should have figured it out in less time than it took me, but it stumped a lot of other people, including everyone who read it on SO. (It only got marked as a duplicate after it had been answered.)
I looked through the Big Null Pointer Question before I posted this, and the answer to my question is not there.
