whats the meaning of this error message?

java.lang.NullPointerException

at UpdateServlet.doPost(UpdateServlet.java:58)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)

at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)

at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)

at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)

at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)

at java.lang.Thread.run(Thread.java:595)

i am using tomcat 5 and everytime data are sent to the servlet, i get this...

[1600 byte] By [ketsona] at [2007-10-3 0:04:39]
# 1

Well, you need to verify your variables really have a value before you try to use them, e.g.

if ((request.getParameter("firstName") != null) && (!request.getParameter("firstName").trim().equals(""))) {

//ok to compare firstName to something or whatever

}

The cause of your exception could be anything really but without code it's impossible to help.

Ashama at 2007-7-14 16:52:43 > top of Java-index,Enterprise & Remote Computing,Web Tier APIs...