Home/ Questions/Q 8418953
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-10T02:28:21+00:00

The following line : <%! ServletContext context = getServletContext(); %> in the jsp page

  • 0

The following line :

<%! ServletContext context = getServletContext(); %>

in the jsp page generates the following errors :

Uncaught exception from servlet
javax.servlet.UnavailableException: java.lang.NullPointerException
at org.mortbay.jetty.servlet.ServletHolder.makeUnavailable(ServletHolder.java:415)
at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:458)
at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:102)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:249)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:135)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:447)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:452)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:458)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:698)
.
.
.

The web application is running on GAE (google appengine). What could be the reason I am getting this error ? What wrong am I doing when I use the above statement in the jsp ?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    With that <%! %> you’re basically declaring an instance variable, so it get initialized during instantiation, however ServletContext is only available by getServletContext() after the init(ServletConfig) has been called. It’s impossible to call that instance method before instantiation, simply because before instantiation there’s no means of an instance.

    I’m not sure why you need this. Perhaps you weren’t aware about the implicit variable application which is already available in the scriptlet scope? This already represents the ServletContext. Just use it directly when necessary. E.g.

    <% application.setAttribute("foo", "bar"); %>

    Unrelated to the concrete technical problem, you’ve a design problem: Java code in JSP files should be avoided.

    • 0