error page mapping

[Rajeev roushan sharma]

Hi ALL, I have mapped error page in DD.

<error-page>
  <error-code>404</error-code>
  <location>/views/erorpage.jsp</location>
</error-page>

And I am setting error from servlet like

response.sendError(404);

.
errorpage.jsp:

<%@ page isErrorPage="true" %>
<h1>We are looking into the issue, please get back in some time...<%= exception.getMessage() %></h1>

Getting below ERROR in console:
SEVERE: Exception Processing ErrorPage[errorCode=404, location=/views/erorpage.jsp]
org.apache.jasper.JasperException: java.lang.NullPointerException
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:630)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:438)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:424)
at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:343)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:144)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at org.apache.jsp.views.erorpage_jsp._jspService(erorpage_jsp.java:60)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)

I am not able to understand why NulllPointer exception is coming. Please let me know how can we pring error msg in jsp.
Your help will be highly appreciated...

[Bear Bibeault]

You need to check exception for null. In the case of a 404, for example, there is no exception.

[Jessid Leon Velez Gutierrez]

Bear Bibeault wrote:You need to check exception for null. In the case of a 404, for example, there is no exception.

Hello Bear... I know i am not who started this thread, but I am interested in this question. Could you please explain a little more your answer. I understand that Rajeev has set an error code of 404 and it is exactly that one that is sending as an error...so what is this about null? thanks a lot!

[Bear Bibeault]

There are a number of errors with this code:

<%= exception.getMessage() %>

Firstly, using scriptlets in a JSP is a poor practice that should have been eradicated years ago. Bad idea.

Secondly, the code assues that the variable exception is not null. This is an invalid assumption. Hence, when it is null, a null pointer exception is raised.

[Jessid Leon Velez Gutierrez]

Bear Bibeault wrote:There are a number of errors with this code:

<%= exception.getMessage() %>

Firstly, using scriptlets in a JSP is a poor practice that should have been eradicated years ago. Bad idea.

Secondly, the code assues that the variable exception is not null. This is an invalid assumption. Hence, when it is null, a null pointer exception is raised.

I get it now. Thanks a lot!

[Rajeev roushan sharma]

Bear Bibeault wrote:There are a number of errors with this code:

<%= exception.getMessage() %>

Firstly, using scriptlets in a JSP is a poor practice that should have been eradicated years ago. Bad idea.

Secondly, the code assues that the variable exception is not null. This is an invalid assumption. Hence, when it is null, a null pointer exception is raised.

Thanks a lot Bear but the it is only test code not for production.

[Bear Bibeault]

Matters not. Practice good habits at all times and it becomes second nature.