@MultipartConfig override in web.xml

Question

So I have this servlet:

@WebServlet(name = "StudentRegistrationUsn", urlPatterns = {"/university/student/registration"}) @MultipartConfig(maxFileSize = 10*1024*1024,maxRequestSize = 20*1024*1024,fileSizeThreshold = 5*1024*1024) public class ActionRegistrationServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //handle file upload } 

Everything works fine, files are uploaded. Then I try to override fileSize and Threshold in web.xml:

  <servlet> <servlet-name>StudentRegistrationUsn</servlet-name> <multipart-config> <max-file-size>10485760</max-file-size> <max-request-size>20971520</max-request-size> <file-size-threshold>5242880</file-size-threshold> </multipart-config> </servlet> 

When I do this, tomcat crashes, and whenever I try to access this servlet, it gives the following exception:

 The server encountered an internal error that prevented it from fulfilling this request. exception java.lang.NullPointerException sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) java.lang.ClassLoader.loadClass(ClassLoader.java:356) org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1629) org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559) org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:461) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002) org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585) org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1813) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) java.lang.Thread.run(Thread.java:722) 

Answer 1

There is no <servlet-class> in web.xml . This exception is mainly caused by the fact that the name of the loaded class is null .

In fact, you need to redefine everything, including URL patterns.

 <servlet> <servlet-name>StudentRegistrationUsn</servlet-name> <servlet-class>com.example.StudentRegistrationUsn</servlet-class> <multipart-config> <max-file-size>10485760</max-file-size> <max-request-size>20971520</max-request-size> <file-size-threshold>5242880</file-size-threshold> </multipart-config> </servlet> <servlet-mapping> <servlet-name>StudentRegistrationUsn</servlet-name> <url-pattern>/university/student/registration</url-pattern> </servlet-mapping>