springmvc osx windows servlet maven

Question

I got a webapp. It works fine on iosx. But if I import the project(mavenproject) into my virtualbox to windows 10(clone with git and import into eclipse with mavenproject). If I want to upload something to the server I get an error."The requested resource is not available." To see the uploadpage I got the following controller:

@RequestMapping(value = "/erstellen", method = RequestMethod.GET)
    public String zeigErstellenForm() {
        System.out.println("im here");
        return "dateien_upload_erstellen";
    }

Its possible to see the uploadpage so I guess this function is called but it doesn't print "im here". I can't understand whats going on.

Error in browser:

type Exception report

message Request processing failed; nested exception is java.lang.NullPointerException

description The server encountered an internal error that prevented it from fulfilling this request.

exception org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981) org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871) javax.servlet.http.HttpServlet.service(HttpServlet.java:648) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845) javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause java.lang.NullPointerException de.bla.blabla.Services.OrdnerErstellen.namePruefen(OrdnerErstellen.java:52) de.bla.blabla.Services.OrdnerErstellen.randomName(OrdnerErstellen.java:33) de.bla.blabla.Services.OrdnerErstellen.(OrdnerErstellen.java:17) de.bla.blabla.Controller.DateiUploadController.save(DateiUploadController.java:52) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) java.lang.reflect.Method.invoke(Unknown Source) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:178) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:444) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:432) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969) org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871) javax.servlet.http.HttpServlet.service(HttpServlet.java:648) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845) javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Error in eclipse:

SCHWERWIEGEND: Servlet.service() for servlet [test] in context with path [/testMaven] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause java.lang.NullPointerException at de.bla.blabla.Services.OrdnerErstellen.namePruefen(OrdnerErstellen.java:52) at de.bla.blabla.Services.OrdnerErstellen.randomName(OrdnerErstellen.java:33) at de.bla.blabla.Services.OrdnerErstellen.(OrdnerErstellen.java:17) at de.bla.blabla.Controller.DateiUploadController.save(DateiUploadController.java:52) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:178) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:444) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:432) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871) at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Unknown Source)

I use:

• tomcat 8
• eclipse

servlet:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

<context:component-scan base-package="de.bla.blabla.Controller"/>


 <bean id="multipartResolver"
  class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>

<mvc:annotation-driven />
<mvc:resources mapping="/resources/**" location="/resources/"/>

  <bean id="jspViewResolver"
    class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass"
            value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
  </bean>
</beans>

web.xml:

<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">  <display-name>test</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>test</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
        <servlet-name>test</servlet-name>
        <url-pattern>*.html</url-pattern>
        <url-pattern>/download</url-pattern>
        <url-pattern>/read</url-pattern>
    </servlet-mapping>

</web-app>

There are no errors in the project. I clean everything updated maven etc.

Answer 1

You can not display a sysout message inside a JSP!

In the WEB-INF/jsp directory of your webapp, create a file index.jsp and write inside these JSP, your helloWorld message.

It will work unless you have missed something else.

Or if you want to use the Model, something like below inside your controller :

ModelAndView mav = new ModelAndView();
mav.addObject("message", "hello world");
return mav;

For your nullpointer exception, I will try remote debugging with your eclipse platform, and make some breakpoints inside the lines :

de.bla.blabla.Services.OrdnerErstellen.namePruefen(OrdnerErstellen.java:52)

at de.bla.blabla.Services.OrdnerErstellen.randomName(OrdnerErstellen.java:33)

at de.bla.blabla.Services.OrdnerErstellen.(OrdnerErstellen.java:17)

at de.bla.blabla.Controller.DateiUploadController.save(DateiUploadController.java:52)