Debugging Jni Dll with VC6

Question

I'm having problems debugging my JNI DLL hosted by a tomcat application. Starting Tomcat under the vc debugger causes a lot of first chance exceptions (0c0000005) to be thrown by JVM.DLL. This happens before my jni dll is even loaded, here's a short dump :
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Geladene Symbole für "D:\Projekte\Applications\Winlog.web\tomcat\bin\JGimp.dll" überein. <----- my JNI DLL
Nicht abgefangene Ausnahme in java.exe (JVM.DLL): 0xC0000005: Access Violation.
Geladene Symbole für "D:\Projekte\Applications\Winlog.web\tomcat\bin\CGimp.dll"
JVM seems to catch those itself, but needless to say, this is something that shouldn't happen.
Any ideas ?
Regards

Answer 1

805541 wrote:
Actually, this was a statement waiting for opinions...
I can use VC2005, VC2008, WinDebug as well, same issue.
And the real alternative is to have strict layering in the C code itself such that you shouldn't need to debug JNI itself at all.well, that's a strange comment. Is there any valid reason not to debug a jni DLL ?1. Because you can't. Say on a production system with strict install rules.
2. Because you don't actually need to "debug" the JNI code itself because you maintain a strict boundary layer protocol. Thus bugs can normally only be expected in the functional C code (which allows for testing via other means.)
3. Because it is difficult to do.
And my favorite is because I would avoid JNI completely these days and instead use a separate executable that wraps the target functionality. Thus to discrete applications both which can be tested independently.
When I used JNI in the past I never needed to use a debugger (because I followed item 2 in the above.)
Other than that I can only see that you have two questions.
1. You are asking if you are doing something wrong. You might suggest googling.
2. You know you are not doing anything wrong and there is something 'wrong' with the VM. In that case get use to it. It isn't going away. Or at least not unless you have a sales contract and/or service contract with Sun/Oracle. And if you have that then this is site is not the appropriate way to use that.