Mobile Application - Device Null Pointer Exception

[kiran nyala]

Hi

I am trying to find whether the request is from mobile/tablet/normal browser. For that I followed below configuration

I have added spring-mobile-device1.0 jar to class path.


spring.xml
----------------

<mvc:interceptors>
    <beans:bean class="org.springframework.mobile.device.DeviceResolverHandlerInterceptor" />
</mvc:interceptors>

web.xml
------------

<filter>
		<display-name>RequestProcessFilter</display-name>
		<filter-name>RequestProcessFilter</filter-name>
		<filter-class>com.test.filter.RequestProcessFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>RequestProcessFilter</filter-name>
		<url-pattern>*.do</url-pattern>
	</filter-mapping>

SessionFilter.java
--------------------

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.mobile.device.Device;
import org.springframework.mobile.device.DeviceUtils;
import org.springframework.web.filter.RequestContextFilter;
public class RequestProcessFilter extends RequestContextFilter {

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterchain) throws ServletException, IOException {
		Device currentDevice = DeviceUtils.getCurrentDevice(request);
		System.out.println(currentDevice.isMobile());
		System.out.println(currentDevice.isNormal());
		System.out.println(currentDevice.isTablet());
               
                   //do other stuff


           }
 }

Problem: Null Pointer Exception at : Device currentDevice = DeviceUtils.getCurrentDevice(request);

Could any one please assist to resolve this issue..

[Jayesh A Lalwani]

Can you post the complete stack trace?

[kiran nyala]

Here is stack trace

[5/5/14 20:19:53:297 IST] 000009fd webapp        E com.ibm.ws.webcontainer.webapp.WebApp logServletError SRVE0293E: [Servlet Error]-[olvr]: java.lang.NullPointerException
	at com.test.filter.RequestProcessFilter.doFilterInternal(RequestProcessFilter.java:14)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:195)
	at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:91)
	at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:928)
	at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1025)
	at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:87)
	at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:895)
	at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1662)
	at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:195)
	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:459)
	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:526)
	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:312)
	at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:283)
	at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214)
	at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113)
	at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
	at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
	at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
	at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
	at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
	at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775)
	at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
	at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1814)

[Jayesh A Lalwani]

That's very weird that you would have a Null Pointer Exception on a call to a static method. Are you sure there is no "Caused by" below that stack trace?. Are you sure line 14 is DeviceUtils.getcurrentDevice Do you have a catch clause inside DeviceUtils.getCurrentDevice method?

[Miguel schwindt]

Did any one solve this problem? Because I'm getting the same as you.

Here is the Class where I'm using the DeviceUtils.getCurrentDevice(request);

import java.util.Collection;
import java.util.Date;

import javax.servlet.http.HttpServletRequest;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mobile.device.Device;
import org.springframework.mobile.device.DeviceUtils;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.WebAuthenticationDetails;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;


@Aspect
public class AuditAspect {
@Before(...)
public void logBefore(JoinPoint joinPoint) {
		HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
		.....
                Device device = DeviceUtils.getCurrentDevice(request);
		
		try{
			if (device.isMobile()){
		           .....
			}
			if (device.isTablet()){
				.....
			}
			if (device.isNormal()){
				.....
			}
		}
		}
		catch(Exception e ){
			e.printStackTrace();
						
		}
		.....
	}	

Here is my stacktrace error, pretty weird because I'm not getting the cause of the error in the trace...

java.lang.NullPointerException
	at com.mstechnology.aop.AuditAspect.logBefore(AuditAspect.java:49)
	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.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:603)
	at org.springframework.aop.aspectj.AspectJMethodBeforeAdvice.before(AspectJMethodBeforeAdvice.java:39)
	at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:64)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at $Proxy57.updateByID(Unknown Source)
	at com.mstechnology.controller.MedicoController.updateMedico(MedicoController.java:103)
	at com.mstechnology.controller.MedicoController$$FastClassByCGLIB$$a1634308.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:698)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
	at org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:64)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:631)
	at com.mstechnology.controller.MedicoController$$EnhancerByCGLIB$$6030699b.updateMedico(<generated>)
	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: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:644)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:301)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:64)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:105)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:125)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.access.channel.ChannelProcessingFilter.doFilter(ChannelProcessingFilter.java:144)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
	at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	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:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:74)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
	at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:676)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:526)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1017)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:652)
	at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1575)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1533)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
	at java.lang.Thread.run(Thread.java:722)