Servlet NullPointerException

I am getting an HTTP 500 error when I dispatch a request from a login servlet to a registration servlet. I am calling the Registration's servlet doGet method from the doGet method of the login servlet using the RequestDispatcher object. When I call the Registration servlet directly from the browser I do not get any errors, but I am getting an error when the doGet method of the Registration servlet is invoked from the login servlet.

Below is the error message I am getting:

HTTP Status 500 -

--

type Exception report

message

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

exception

java.lang.NullPointerException

at SubscriptionServlet.doPost(SubscriptionServlet.java:185)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)

at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:432)

at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:356)

at LoginServlet.doGet(LoginServlet.java:36)

at LoginServlet.doPost(LoginServlet.java:93)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:260)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)

at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2396)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)

at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)

at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)

at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:405)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:380)

at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:508)

at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:533)

at java.lang.Thread.run(Thread.java:536)

--

Apache Tomcat/4.1.12-LE-jdk14

I would appreciate any help.

[4252 byte] By [newtona] at [2007-11-26 19:43:45]
# 1
I'll bet your login servlet does not point to the correct Registration servlet, or that you have not instantiated something. Some code would be helpful to look at. Be sure to use code tags if you post any.
Djaunla at 2007-7-9 22:27:15 > top of Java-index,Java Essentials,Java Programming...
# 2
Your doPost() method has a problem; SubscriptionServlet.java line 185
tschodta at 2007-7-9 22:27:15 > top of Java-index,Java Essentials,Java Programming...
# 3
Thanks for your help, my problem was that I declared some String variables in the dopost method without initializing them. I wanted to initialize these variables fron the parameters returned. These parameters where null and thus an exception was raised.
newtona at 2007-7-9 22:27:15 > top of Java-index,Java Essentials,Java Programming...