[opencms-dev] NPE during module development

[Jorg Heymans]

Hi ,

I have written several fairly large modules using the 
Contentdefinition/Backoffice paradigm. The process of learning how to do 
this and what bugs to avoid was painfull and long. Just when I thought 
i'ld seen it all, my code hits another nasty nullpointerexception in the 
opencms core.

This npe does not occur when I "delete" a contentdefinition or "create" 
a new one, it only occurs when i "edit" an existing one. Any idea or 
pointer at all as to where I could look for this error would be 
appreciated. I have stripped down all relevant classes and methods to 
just logging statements and the error still occurs. I did the same for 
my templates to no avail. I also cleared the tomcat cache (this has 
solved unexplainable things before) without success.

Does the following stacktrace look familiar to any of the developers ?

java.lang.NullPointerException
    at 
com.opencms.defaults.A_CmsBackoffice.getContentEditInternal(A_CmsBackoffice.java:3096)
    at 
com.opencms.defaults.A_CmsBackoffice.getContent(A_CmsBackoffice.java:442)
    at 
com.opencms.template.cache.CmsElementXml.getContent(CmsElementXml.java:169)
    at com.opencms.template.cache.CmsUri.callCanonicalRoot(CmsUri.java:169)
    at 
com.opencms.template.cache.CmsElementCache.callCanonicalRoot(CmsElementCache.java:148)
    at 
com.opencms.launcher.CmsXmlLauncher.generateOutput(CmsXmlLauncher.java:228)
    at com.opencms.launcher.CmsXmlLauncher.launch(CmsXmlLauncher.java:283)
    at com.opencms.launcher.A_CmsLauncher.initlaunch(A_CmsLauncher.java:272)
    at com.opencms.core.OpenCms.showResource(OpenCms.java:588)
    at 
com.opencms.core.OpenCmsHttpServlet.doGet(OpenCmsHttpServlet.java:223)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at com.opencms.boot.OpenCmsServlet.service(OpenCmsServlet.java:117)
    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:2415)
    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$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
    at 
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:509)
    at 
org.apache.catalina.core.StandardPipeline$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$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
    at 
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
    at 
org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
    at 
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:432)
    at 
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:386)
    at 
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:534)
    at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:530)
    at java.lang.Thread.run(Thread.java:536)

Thanks
Jorg Heymans