Re: Problem with JVM 1.4.2 on Cygwin 1.5.5-1 on XP and 2000

[Igor Pechtchanski <pechtcha at cs dot nyu dot edu>]

On Fri, 9 Jan 2004, Moy Easwaran wrote:

> I'm trying to run HelloWorld.java on a JVM invoked from C.  I'm using
> the basic setup in David Caldwell's excellent how-to at
> <http://www.inonit.com/cygwin/jni/invocationApi/> et seq.
>
> It works fine on WinNT 4.0 and WinXP Home, but dies on WinXP Pro and
> Win2000.
>
> There's not really much of a trail I can provide.  I get a message-box
> saying: "jvm.exe has encountered a problem and needs to close.  We are
> sorry for the invonvenience."
>
> It dies on JNI_CreateJavaVM with the 1.4.1 SDK.  In 1.4.2,
> JNI_CreateJavaVM always returns -1 (and so FindClass can't run).
>
> The Windows event log says:
> "Faulting application jvm.exe [my executable], version 0.0.0.0,
> faulting module jvm.dll, version 0.0.0.0, fault address 0x000a9d63.
> Application Failure jvm.exe 0.0.0.0 in jvm.dll 0.0.0.0 at offset
> 000a9d63.."
>
> Any suggestions on where to look or what to look for?  Help!
>
> Thanks much,
>
> Moy

Moy,

Technically, since you're using -mno-cygwin, this is not a Cygwin problem.
You could probably get better answers on the MinGW-users list (see
<http://mingw.org/>).  However, I have a couple of guesses inline below
that might be helpful.

> My steps and files are as follows:
>
> $ dlltool --input-def jvm.def --kill-at --dllname jvm.dll --output-lib libjvm.dll.a

Where is this jvm.dll coming from?

> $ gcc -Wall -mno-cygwin -o jvm.exe -I/cygdrive/c/j2sdk1.4.1_06/include -I/cygdrive/c/j2sdk1.4.1_06/include/win32 jvm.c -L. -ljvm
> $ cat jvm.def
> EXPORTS
> JNI_CreateJavaVM@12
> JNI_GetDefaultJavaVMInitArgs@4
> JNI_GetCreatedJavaVMs@12

Are you sure you got the right argument patterns here (i.e., numbers after
the '@' sign)?  That may be one source of the problem.

> $ cat HelloWorld.java
> public class HelloWorld
> {
>     public static void main (String args [])
>     {
>         System.out.println ("Hello, world!");
>     }
> }
>
> $ cat jvm.c     # this is basically the invoke.c example on inonit.com
> #include <stdio.h>
> #include <jni.h>
>
> JNIEnv* create_vm() {
>         JavaVM* jvm;
>         JNIEnv* env;
>         JavaVMInitArgs args;
>         JavaVMOption options[1];
>     int res;
>
>         /* There is a new JNI_VERSION_1_4, but it doesn't add anything for the purposes of our example. */
>         args.version = JNI_VERSION_1_2;
>         args.nOptions = 1;
>         options[0].optionString = "-Djava.class.path=c:\\test";

Shouldn't this also contain a pointer to the default class libraries?

>         args.options = options;
>         args.ignoreUnrecognized = JNI_TRUE;
>
>     printf ("about to call CreateJavaVM.\n");
>         res = JNI_CreateJavaVM(&jvm, (void **)&env, &args);
>     printf ("CreateJavaVM returned [%d].\n", res);
>         return env;
> }
>
> void invoke_class(JNIEnv* env) {
>         jclass helloWorldClass;
>         jmethodID mainMethod;
>         jobjectArray applicationArgs;
>         jstring applicationArg0;
>
>     printf ("step 2...\n");
>         helloWorldClass = (*env)->FindClass(env, "HelloWorld");
>
>     printf ("step 3...\n");
>         mainMethod = (*env)->GetStaticMethodID(env, helloWorldClass, "main", "([Ljava/lang/String;)V");
>
>     printf ("step 4...\n");
>         applicationArgs = (*env)->NewObjectArray(env, 1, (*env)->FindClass(env, "java/lang/String"), NULL);
>         applicationArg0 = (*env)->NewStringUTF(env, "From-C-program");
>         // (*env)->SetObjectArrayElement(env, applicationArgs, 0, applicationArg0);
>
>     printf ("step 5...\n");
>         (*env)->CallStaticVoidMethod(env, helloWorldClass, mainMethod, applicationArgs);
> }
>
> int main(int argc, char **argv) {
>         JNIEnv* env = create_vm();
>     printf ("step 1 done...\n");
>         invoke_class( env );
>     return 0;
> }

HTH,
	Igor
-- 
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