nullPointerException while linking jsp file to mysql - mysql

HTTP Status 500 - Internal Server Error
type Exception report
messageInternal Server Error
descriptionThe server encountered an internal error that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: java.lang.NullPointerException
root cause
java.lang.NullPointerException
note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 4.0 logs.
GlassFish Server Open Source Edition 4.0
I'm not able to open the stack trace. the log file under domain is empty. pls help

NullPointerException means you are trying to call a non-static method (or an attribute) of an object which is not defined.
Example:
String s = "Foo";
System.out.println(s.length());
This code prints 3, because the length of Foo is 3, and s has been initialized as Foo.
Example with NullPointerException:
String s = null;
System.out.println(s.length());
Here s is null and I try to call the method length(), which is a non-static method. Obviously I will get a NullPointerException: there is no sense to get the length of "nothing" (null).
Nevertheless, you still can call static methods with s:
String s = null;
System.out.println(s.valueOf('a'));
Prints a. Note that it is not a good way to call static methods.
The static method valueOf(char) from the type String should be accessed in a static way
This warning explains you should access valueOf(char) this way:
System.out.println(String.valueOf('a'));
Now I let you find the error in your code because you didn't share it.

Related

Actual exception is not getting logged in MVC when host in IIS

I am running one MVC application where i found one exception in specific method. I will provide here complete details about it.
I am loading some third party grid control from view. to load it i used below code:
#{Html.RenderAction("MasterGridAction", "MyController");}
Now when i access this report from development then this view load and it hits this action method where i used some piece of code there it is throwing error, To catch the error i used try catch block in the method where in catch section i used below code to throw the actual exception like below:
catch (Exception ex)
{
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(ex).Throw(); throw;
}
When exception get catched it sends this to the Application_Error method in global.asax page where i used below code to find out the actual exception like below:
void Application_Error(object sender, EventArgs e)
{
HttpServerUtility server = HttpContext.Current.Server;
if (server.GetLastError() != null)
{
Exception exception = server.GetLastError();
if (exception.GetBaseException() != null)
{
exception = exception.GetBaseException();
ExceptionType(server, exception);
}
else
{
ExceptionType(server, exception);
}
}
}
In this ExceptionType method i get the exception stack and log to the file using "Log4Net". After logging to the file i could see the exception in notepad like below:
Object reference not set to an instance of an object.
Source File: /MyController/MasterGridAction
Stack Trace:
at 3D.Controllers.MyController.MasterGridAction() in D:\MyUser\3D_MVC\Application\3D_OnlyRelease\3D\Controllers\MyController.cs:line 405
--- End of stack trace from previous location where exception was thrown ---
As we can see in above exception it is clearly shown the line number also where this exception get caught.
But once i host this application in IIS server and access the same page then i could see the logged file
There it shows exception like below:
Exception Message: Object reference not set to an instance of an object.
Stack Trace: at 3D.Controllers.MyController.MasterGridAction()
--- End of stack trace from previous location where exception was thrown ---
As you can see the logged exception of IIS server is not having much information when compare to other exception details.
Am i missing anything there to get the complete exception when host in IIS?
Please suggest.
As you can see the logged exception of IIS server is not having much information when compare to other exception details.
This could be because you don't include the PDB files in production.
It might not be a great idea to include them, since that way one can reverse engineer you app with more precision if they hack your server, but it is up to you to decide. I have seen organizations that include them in their production environments.
Try publishing and deploying on a test environment with and without the PDB files to verify this.

RESTier Submit Logic, push error message to top level

I am using RESTier 0.6.0 library and would like to perform some checks on a resource before deleting it. In the event that the checks fail, I am throwing an Exception to stop the delete operation. However, the error message that I am using to instantiate the Exception is not getting pushed out at the highest level. I can only view the message as an inner exception when serving my Web API from Visual Studio. Is there a way to get this error message to push out at the highest level?
protected void OnDeletingGw_Pack(Gw_Pack pack)
{
var trades = ModelContext.Gw_PackJunction.Where(e => e.PackID == pack.PackID).ToList();
if (pack.Groupage == true || trades.Count > 1)
{
// Don't delete a pack if it is a groupage container or if it's associated with more than one Trade.
throw new Exception("The container you are trying to delete is either marked as groupage or is functioning as a groupage container in another file.");
}
}
Currently any Exception thrown within the OnDelete submit logic methods in the EntityFrameworkApi results in an error which looks like this:
{
"error":{
"code":"","message":"An error has occurred."
}
}
... which is not particularly useful to the client.
UPDATE: I noted in the RESTier documentation MkDocs version that an example was given where an ODataException (rather than Exception) was thrown. I changed this in my code, but the error object returned by the published Restier service still only has the basic "An error has occurred" information.
Assistance is greatly appreciated!
When throwing an Exception within the RESTier EntityFrameworkApi (inside and OnUpdate<EntitySet> method for example), the exception is deserialized as part of the inner exception (internalexception). So in order to view any exceptions thrown within the RESTier API, one needs to...
set the IncludeErrorDetailPolicy property on the HttpConfiguration
class like this:
config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always
Structure of error received by client
See this post: OData controller returns different error for local and different for remote machine

The noticeError method was not found. while using Coldbox and NewRelic for Error tracking

I'm just using NewRelic error trapping for my coldbox application. From OnException method, I'm just sending the error struct to log the error.
My code in onexception method
public function onException(event,rc,prc){
NewRelic.logError( prc.exception.getExceptionStruct());
}
The logerror() method resides in NewRelic.cfc and contains the following code
public boolean function logError(
required struct exception
) {
var cause = arguments.exception;
var params = {
error_id = createUUID(),
type: arguments.exception.type,
message: arguments.exception.message
};
writeDump(this.newRelic);
this.newRelic.noticeError(cause, params);abort;
return true;
}
So while error, I'm gettig the following error.
The noticeError method was not found.
You can see that, the noticeError() method is there in the object, but it is overloaded with arguments.
I'm using the same code for NewRelic error trapping in another coldfusion project without any frameworks.
Calling error.cfm through Cferror tag, and the code in error.cfm as follows
<cfset Application.newRelic.logError( variables.error )>
And in NewRelic.cfc, the logerror() method contains the same code as in the coldbox application. But it is logging errors in NewRelic without any issues.
This is the method I need to notice errors and log it in NewRelic.
noticeError(java.lang.Throwable, java.util.Map)
So I just thought to get the classname of the first argument Cause through the following code from both applications within logError() in NewRelic.cfc, to get the difference.
writeDump(cause.getClass().getName());
I'm getting
coldfusion.runtime.ExceptionScope for Coldbox application
and
coldfusion.runtime.UndefinedVariableException for normal coldfusion application
The cause argument is not throwable from coldbox application. So how to get the original error struct from coldbox application? and make it throwable to fix the noticeError method was not found issue.
The change in the underlying class happens when ColdBox duplicates the error object with CFML's duplicate() method. I doubt that ColdFusion behavior is documented anywhere, but I don't see an easy way to get around it right now other than creating your own instance of a java.langException and populating it with the details of the original error.
If you want to modify the ColdBox core code, this happens here:
https://github.com/ColdBox/coldbox-platform/blob/master/system/web/context/ExceptionBean.cfc#L43
I have entered this ticket for the ColdBox framework for us to review if we can stop duplicating the error object in future versions of the framework.
https://ortussolutions.atlassian.net/browse/COLDBOX-476
Update: Adam Cameron pointed out this ticket in the Adobe bug tracker that details this behavior in the engine. It was closed as "neverFix".
https://bugbase.adobe.com/index.cfm?event=bug&id=3976478

System.TypeInitializationException between two program in F#

I'm working on a project and I become always an Exception "TypeInitializationException".
I tried to give a string to a global string variable but it failed.
That's the code for the viewmodel and it failed on the second line
| {State = _}, ConsumablesClicked vm ->
Testtyp <- vm.TrackPosition.ToString()
That's on the other program
let mutable Testtyp = ""
I become this InnerException "Cannot read keys when either application does not have a console or when console input has been redirected from a file. Try Console.Read.".
"The type initializer for '.$BarcodeGenerieren' threw an exception.", that's the exception explication.
Has someone a Idea how solve this?
That exception indicates that some code is trying to call Console.ReadKey when the standard input for that process has been redirected (see e.g. Allowing redirection of StandardInput of a C# application when doing "Console.ReadKey"). The solution is not to call Console.ReadKey, but it's not clear from your description where this is actually happening (perhaps in the static constructor for one of your types?).
I found the solution after a lot of try and it was only, that I had a Console.Readkey in my code, that I forgot to delete.
I had before a console apllication and I transformed it to be a class.

How to return stack Trace to Client in MULE..?

Does anybody know how to print full stack trace on the Browser, when a Runtime Exception occurs in MULE..??
When a runtime Exception occurs, MULE throws a 500 Server Error to the client , but shows no details to the client. It prints the whole stack trace in Console or Log Files (like the following) :
Root Exception stack trace:
java.sql.SQLException: Invalid column name
at oracle.jdbc.driver.OracleStatement.getColumnIndex(OracleStatement.java:3677)
at oracle.jdbc.driver.OracleResultSetImpl.findColumn(OracleResultSetImpl.java:2749)
at oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:494)
+ 3 more (set debug level logging or '-Dmule.verbose.exceptions=true'
for everything)
Can i show the same stack Trace on the Browser (to the client)..??
And if possible , then also tell me how to switch ON or OFF printing of Stack Trace on Browser..??
(It may be possible that sometime in future , i dont want to show stack trace on browser)
Yes this is possible. I assume you are using a regular HTTP endpoint and this is a REST type service(?) If so, you can simply put a try/catch around the code causing the exception and return whatever text you want.
There are also exception strategies (http://www.mulesoft.org/documentation/display/MULE3USER/Error+Handling) for doing more sophisticated error handling, but it sounds like you are looking for the simple answer above.
If this doesn't answer your question, please provide more info about your mule config and the service that is raising the exception.
There is nothing out of the box in Mule to do that. You have to implement an exception handler that will format the stacktrace in the Message exception payload and return it to the caller.
In your case, the HTTP transport has a particularity that can be found in the HttpMessageReceiver code:
try
{
conn.writeResponse(processRequest(request));
}
catch (Exception e)
{
...
conn.writeResponse(buildFailureResponse(request.getRequestLine().getHttpVersion(), httpStatus, e.getMessage()));
This means that when an exception crops-up to the top level, the creation of the failure message response is not customizable: you get this pretty technical message back and that is all.
I see two options to solve your problem:
sub-class HttpMessageReceiver and make the response message customizable in your version,
drop the HTTP transport in favor of the Jetty one (look at the bookstore example) and customize the response error messages at the web container level.