The following message can be found in the server log in the file system on the Domino server:
java.lang.NullPointerException
at com.ibm.xsp.component.UIDataPanelBase.encodeEnd(UIDataPanelBase.java:280)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:856)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:851)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:851)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:851)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:851)
at com.ibm.xsp.util.FacesUtil.renderComponent(FacesUtil.java:851)
at com.ibm.xsp.component.UIViewRootEx._renderView(UIViewRootEx.java:1317)
at com.ibm.xsp.component.UIViewRootEx.renderView(UIViewRootEx.java:1255)
at com.ibm.xsp.application.ViewHandlerExImpl.doRender(ViewHandlerExImpl.java:641)
at com.ibm.xsp.application.ViewHandlerExImpl._renderView(ViewHandlerExImpl.java:320)
at com.ibm.xsp.application.ViewHandlerExImpl.renderView(ViewHandlerExImpl.java:335)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:103)
at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:210)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:120)
at com.ibm.xsp.controller.FacesControllerImpl.render(FacesControllerImpl.java:264)
at com.ibm.xsp.webapp.FacesServlet.serviceView(FacesServlet.java:219)
at com.ibm.xsp.webapp.FacesServletEx.serviceView(FacesServletEx.java:204)
at com.ibm.xsp.webapp.FacesServlet.service(FacesServlet.java:160)
at com.ibm.xsp.webapp.FacesServletEx.service(FacesServletEx.java:138)
at com.ibm.xsp.webapp.DesignerFacesServlet.service(DesignerFacesServlet.java:103)
at com.ibm.designer.runtime.domino.adapter.ComponentModule.invokeServlet(ComponentModule.java:583)
at com.ibm.domino.xsp.module.nsf.NSFComponentModule.invokeServlet(NSFComponentModule.java:1281)
at com.ibm.designer.runtime.domino.adapter.ComponentModule$AdapterInvoker.invokeServlet(ComponentModule.java:860)
at com.ibm.designer.runtime.domino.adapter.ComponentModule$ServletInvoker.doService(ComponentModule.java:803)
at com.ibm.designer.runtime.domino.adapter.ComponentModule.doService(ComponentModule.java:572)
at com.ibm.domino.xsp.module.nsf.NSFComponentModule.doService(NSFComponentModule.java:1265)
at com.ibm.domino.xsp.module.nsf.NSFService.doServiceInternal(NSFService.java:658)
at com.ibm.domino.xsp.module.nsf.NSFService.doService(NSFService.java:481)
at com.ibm.designer.runtime.domino.adapter.LCDEnvironment.doService(LCDEnvironment.java:341)
at com.ibm.designer.runtime.domino.adapter.LCDEnvironment.service(LCDEnvironment.java:297)
at com.ibm.domino.xsp.bridge.http.engine.XspCmdManager.service(XspCmdManager.java:272)
Is there any way to get more info about the error? If there is, how to get more details?
First, I would suggest that you install the LogReader from OpenNTF.org by Jakob Majkilde (http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=XPages%20Log%20File%20Reader). It will give you easy access to the various logfiles on the server. You may need to look at different log files for specific issues - sometimes they land in the not so obvious place ;-)
When you have installed the log reader then look at messages just after (or perhaps before) the message above. In many cases several exceptions will be thrown - and you should look for the ones that refer to your own code. Changes are that you have missed initialization of an object in your own code. If you code in Java then the logs will be even more helpful.
In addition you could (should) consider using some kind of logging mechanism in your own code to tell you how far in loading/processing a page you are before failing. You could use the XPages OpenLog Logger: http://www.openntf.org/main.nsf/project.xsp?r=project/XPages%20OpenLog%20Logger
/John
Related
I am trying to develop a standard when I code applications.
I was curious as to what other developers did when it comes to sql errors or general program errors. Do you output the error to the screen, write to a log file, or something else?
It really depends on the severity of the error.
Is it a show stopper?
Can the software automatically retry and get away with no message?
Can it be ignored?
You can log every exception, or just certain ones, or none. I have a custom Exception class which logs every exception created (of that type).
I have an unhandled exception handler which emails me when there is one.
I'd only send a message to the user when it will change the way the application works from the user's point of view.
Your question is a bit subjective and you would get opinion-based answers if the entire community bothered to answer.
If the error is relevant and important to the user (e.g.: invalid username/password) display it to the user using a message box.
If the error is relevant to the developer, or can be used in the debugging process, use a log or a console output.
The trick is to identify which and how the errors should be displayed to the user. You don't want to bombard the user with exceptions and complicated errors on which the user has no idea on how to act upon.
I'm trying to understand WCF message routing, so I'm trying to recreate a sample passthrough router that I found in order to understand the pieces. The problem is that when I run mine in the debugger, I get the exception:
Multiple headers with name 'VsDebuggerCausalityData' and namespace 'http://schemas.microsoft.com/vstudio/diagnostics/servicemodelsink' found.
I've read that this is because I'm debugging all the pieces at the same time, and that the debugger is adding this data on each hop? However, I can debug all the pieces in the original sample I'm working from with no errors, so I'm not sure I believe the explanation I've seen, or I don't understand something yet. Anyone have an explanation how I can debug mine without getting this exception?
Can you check if your machine config has element. You might need to comment this out. (Before any changes to machine config do back it up)
I'm working on a site and to help catch errors that we may not hear about, I've created a custom 500 error page.
This page basically records information about the current situation and logs it including the following:
Request.Servervariables("URL")
But, the log seem to actually be providing information about the location of the error.asp file instead of the actual file causing the error. And it doesn't seem to pick up Server.GetLastError().
Any ideas on how to ensure these scripts pick up the errors and deatils about the page causing the error and not the page that is used for 500 errors?
NOTE: When there's an error, the url in the address bar is always the address fo the page causing the error, but the log shows the error handler page 'error.asp'.
I would follow what Dee said, but also be aware that there was something finicky with IIS7 (or 7.5). I can't remember exactly, but you have to do something special to make sure it works on IIS7. Check out this article. IIS7 breaks the server.getlasterror and there is a workaround provided.
Also a cool thing to do is to email yourself those errors. So in your custom 500 asp script just fire off an email with the details. Depends on how critical errors are to your program, but it's good to be in the loop rather than have another log to worry about.
Generally, in software design, which of the options below is preferred when there is a problem or error with a resource such as a database or file?
Show an error message
Do not show an error message and act as though the resource was empty (eg. do not populate a GUI component)]
For example, should the user see an empty DataGrid following which they complain, or should there be an error message? Which is better?
I don't see this as an either/or. Also, we need to consider all "users" of the system.
First consider the UI. Let's consider a contrived general case: you are populating a UI by calling a service which in turn uses a couple of of databases (for example a "current data" and an "historic data") database.
There are at least these possibilities:
It all works, data is retrieved
It all works but as it happens there's no data for this particular query
Can't reach the service
Service is invoked, but one database is down
Service is invoked, but both databases are down
Then also consider your application's semantics. Can your applciation procede in a "degraded" mode if all the data cannot be retrieved? For example, we can't query the history but that doesn't stop us creating a new item.,
Now also consider the roles here. There's the person using the UI, there's also support and maintenance people who need to know about and fix problems.
My general rules:
First Failure Data capture: Whichever component first detects an error should log it in some detail. So, service up, database down the service should log the problem. Service down, the UI should log the problem. This log should be a technical record targeting the support roles.
UIs should be tolerant: if at all possible run in a degraded mode. So if the service is down but (for example) local working is possible put up an empty screen and continue. BUT ...
Always indicate a problem: The "no data for this query" and "databases unavailable" cases may both result in an empty screen. The user needs to know the status of the display, is it showing complete information, partial information (eg. because one DB is down) or is no information available (eg. service or both dbs down). So have a "Status" field somewhere on the screen. Giving messages such as
Historica Data not currently available
or
There are problems retrieveing
information, if these persist please
contact support ...
There are some pitfalls to each of the options
Showing error message
This is specially helpful when your application is in testing stage or public testing. Also when clients meets an error, he or she can copy down the details and forward to you.
However sometimes this error message gets very ugly (call stacks and so on - remember ASP.NET?) and it becomes so large that it becomes difficult for clients to copy down the details.
Do not show error message and act as though nothing happened =)
This is useful when you don't want error messages to cog up your software UI design. But be reminded that it becomes difficult and further error prone when clients can't differentiate between an actual error, or really nothing on the GUI. The error stays there and nothing gets fixed.
My stand
Get the best of both worlds. In fact most modern applications how have a very good error handling process. I'll take the example of Mozilla Firefox 3.
A deadly error occurred and Firefox crashes
Error is captured and stored into a file as a form of error report
Error Reporting Application pops up apologizing to the user
Ask the user if the user want to send the error report to the software dev team
Then ask the user if want to restart the application
Or if the error is a warning or of lesser severity:
Show a simple error code and tell the user that there's the error with that action. Something like: "Error 123 at RequestSalary() Line 2"
The practice I usualy use is:
If the error didn't happen due to user error, then you should try to handle the error quietly.
If the error occurred because of some external problem (such as no internet connection) then you should alert the user.
IMO you should show a message (albeit a user friendly one and not something like "java.io.IOException: Connection timed out".) You could have a message box telling the user that an error occured while getting the data and provide helpful tips like: Trying after some time, check network cable, etc.
Also allow user to report that error to you (error reporting build into the app) that will send you the actual error and stack trace.
We're using WatiN to test our web portals. During the course of an E2E test, we'll occasionally see client-side script errors on the IE status bar. I'd like to chain a handler onto the script error event and record the error for later analysis and bug filing.
Problem is, I don't know that there's a global script error event or how to chain into it. And if there's not a browser-agnostic way to accomplish this, I can create MyIE and MyFF subclasses but then this becomes two browser-specific questions.
In essence, I'm thinking of something like this entirely made-up call:
browser.ScriptEngine.SetCustomErrorHandler(LogScriptingError);
... where LogScriptErrors is my code that does the obvious.
Many of our client-side scripting errors don't necessarily prevent the test from continuing (a pretty UI element didn't animate, for example, but the underlying form is still submittable), so I'd like to log the error and forge ahead in most cases.
You probably looking for this:
window.onerror=function(message, url, line){logError();};
You can add this code to your pages to handle errors in logError(). but this may not work in all browser(works in IE), check this for browser compatibility:
http://www.quirksmode.org/dom/events/error.html
Or you may try this commercial product:
exceptionhub.com/
You could maybe co-opt the ability to inject eval code (described under "Added Eval functionality") to add a script that caught all errors, not just errors from the eval'ed script. I'm not sure if this would work, but it's an area to explore. Another resource might be this blog post, which discusses how to evaluate Javascript in WatiN.