Help with JDPA failure on JVM Startup from C++ using JNI_CreateJavaVM
The short version:
When I try to start a jvm with the -Xrunjdwp from C++ using JNI_CreateJavaVM and the following settings, it simply crashes. I can run my program just fine when this option is not present.
JavaVMOption aoOptions[5];
aoOptions[0].optionString = m_ustrClassPath.GetStringA();
aoOptions[1].optionString = "-Xdebug";
aoOptions[2].optionString = "-Xnoagent";
aoOptions[3].optionString = "-Djava.compiler=NONE";
aoOptions[4].optionString = "-Xrunjdwp:transport=dt_socket,address=localhost:8000,server=y,suspend=n";
I have all the appropriate jar files on the classpath and the DLL's are on the path. I am running 1.4.2. I have also tried dt_shmem and a combination of most of the adjustable paramaters being on/off or not present. Any help would be greatly appreciated!!!
Thanks,
Chris
The long version (or why I want to do this crazy thing):
I am migrating a product line from Visual Basic/C++/COM to Java. I recently purchased JBuilder 9 with the hope that I could use the attach to running JVM process to debug fully. When I attempted to add the neccessary options, my jvm create dies. I can't get to a point to attach from JBuilder.
[1229 byte] By [
foxxlf23a] at [2007-9-29 6:44:38]
Is there any information available from the crash?
Do you get an error traceback, or a SIGSEGV, or some
other message?
I just tried a simple run based on your command line
and got this error:
% java -Xdebug \
-Xrunjdwp:transport=dt_socket,address=localhost:8000,server=y,suspend=n HelloWorld
Invalid listen port number: localhost:8000
Transport dt_socket failed to initialize, rc = -1.
FATAL ERROR in native method: No transports initialized
Since you have "server=y", this VM will be listening for
an attach and the hostname is not needed (it is implicitly
going to be the machine you are running on). Try this:
% java -Xdebug \
-Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n HelloWorld
Hello, world!
As a side note, the options -Xnoagent and -Djava.compiler=NONE
are obsolete in any HotSpot Virtual Machine. They will be ignored. For
more information:
http://java.sun.com/j2se/1.4.2/docs/guide/jpda/conninv.html
I have finally found a solution...
Please see this bug: http://developer.java.sun.com/developer/bugParade/bugs/4335526.html
The bug has not been fixed but a workaround exists. Please see the bug for full information, the short answer is this.
When using the below settings, the -Xrun option is causing an Access Exception crash within jvm.dll. This seems to be because the -Xrun string is modified within jvm.dll.
JavaVMOption aoOptions[5];
aoOptions[0].optionString = m_ustrClassPath.GetStringA();
aoOptions[1].optionString = "-Xdebug";
aoOptions[2].optionString = "-Xnoagent";
aoOptions[3].optionString = "-Djava.compiler=NONE";
aoOptions[4].optionString = "-Xrunjdwp:transport=dt_socket,address=localhost:8000,server=y,suspend=n";
The solution that worked for me was to use strdup as indicated in the workaround for the bug.
JavaVMOption aoOptions[5];
pTempStrOption = m_ustrClassPath.GetStringA();
aoOptions[0].optionString = strdup(pTempStrOption);
aoOptions[1].optionString = strdup("-Xdebug");
aoOptions[2].optionString = strdup("-Xnoagent");
aoOptions[3].optionString = strdup("-Djava.compiler=NONE");
aoOptions[4].optionString = strdup("-Xrunjdwp:transport=dt_socket,address=3333,server=y");
This has caused me grief for months. It was not easy to locate in the bug database. It existed in 1.3 and still exists as of 1.4.2. I am not sure about the 1.5 beta.
