I've finally hunted down the problem. It stems from the way we (I) handle errors, and is not openAuth specific, it just triggered here. When the virConnectOpen* function encounters an error, it calls the error handler we set in the initializer, which in turn handles the error, and sets a java exception, but DOES NOT RETURN to java land. Next, we try to get the error, which seems to have been cleared after calling the handler. (The deleted code was plain broken anyway, because the error struct is allocated by the virCopyLastError, not the caller), Then we call our error handler function with the uninitialized junk error object, which results in interesting errors. The solution is quite simple, we simply need to return if we are unsuccessful (get NULL vc), and the previously set exception is magically thrown. Generally, we should be much more careful with handling errors and exceptions, but 1.0 is a long way. :-) regards István Daniel Veillard wrote: ? .project ? README.in ? src/jni/org_libvirt_Connect.h ? src/jni/org_libvirt_Domain.h ? src/jni/org_libvirt_Domain_CreateFlags.h ? src/jni/org_libvirt_Domain_MigrateFlags.h ? src/jni/org_libvirt_Domain_XMLFlags.h ? src/jni/org_libvirt_Network.h Index: src/jni/org_libvirt_Connect.c =================================================================== RCS file: /data/cvs/libvirt-java/src/jni/org_libvirt_Connect.c,v retrieving revision 1.1 diff -u -p -r1.1 org_libvirt_Connect.c --- src/jni/org_libvirt_Connect.c 18 Jul 2008 14:37:21 -0000 1.1 +++ src/jni/org_libvirt_Connect.c 21 Jul 2008 18:48:22 -0000 @@ -149,14 +149,13 @@ JNIEXPORT jlong JNICALL Java_org_libvirt (JNIEnv *env, jobject obj, jstring uri){ virConnectPtr vc; - virError error; //Initialize the libvirt VirtConn Object vc=virConnectOpen((*env)->GetStringUTFChars(env, uri, NULL)); if(vc==NULL){ - virCopyLastError(&error); - virErrorHandler(env, &error); - return (jlong)NULL; + //We have a pending java exception, let's return + assert((*env)->ExceptionOccurred(env)); + return NULL; } //Initialized the error handler for this connection @@ -169,14 +168,13 @@ JNIEXPORT jlong JNICALL Java_org_libvirt (JNIEnv *env, jobject obj, jstring uri){ virConnectPtr vc; - virError error; //Initialize the libvirt VirtConn Object vc=virConnectOpenReadOnly((*env)->GetStringUTFChars(env, uri, NULL)); if(vc==NULL){ - virCopyLastError(&error); - virErrorHandler(env, &error); - return (jlong)NULL; + //We have a pending java exception, let's return + assert((*env)->ExceptionOccurred(env)); + return NULL; } //Initialized the error handler for this connection @@ -237,10 +235,9 @@ fprintf(stderr, "calling virConnectOpenA if(vc==NULL){ fprintf(stderr, "Got NULL\n"); - - virCopyLastError(&error); - virErrorHandler(env, &error); - return (jlong)NULL; + //We have a pending java exception, let's return + assert((*env)->ExceptionOccurred(env)); + return NULL; } //Initialize the error handler for this connection