Hi,
I'm trying to work on the JNI invocation APIs.
Platform : Windows XP Professional
JDK : j2sdk1.4.2
C-Compiler : MinGW's gcc.
1.The invoke.c file as follows:
#include <jni.h>
#ifdef _WIN32
#define PATH_SEPARATOR ';'
#else /* UNIX */
#define PATH_SEPARATOR ':'
#endif
#define USER_CLASSPATH "." /* where Prog.class is */
main() {
JNIEnv *env;
JavaVM *jvm;
JDK1_1InitArgs vm_args;
jint res;
jclass cls;
jmethodID mid;
jstring jstr;
jobjectArray args;
char classpath[1024];
/* IMPORTANT: specify vm_args version # if you use JDK1.1.2 and beyond */
vm_args.version = 0x00010001;
// JNI_GetDefaultJavaVMInitArgs(&vm_args);
/* Append USER_CLASSPATH to the end of default system class path */
sprintf(classpath, "%s%c%s",
vm_args.classpath, PATH_SEPARATOR, USER_CLASSPATH);
vm_args.classpath = classpath;
/* Create the
Java VM */
res = JNI_CreateJavaVM(&jvm,(void **)&env,&vm_args);
if (res < 0) {
fprintf(stderr, "Can't create Java VM\n");
exit(1);
}
cls = (*env)->FindClass(env, "Prog");
if (cls == 0) {
fprintf(stderr, "Can't find Prog class\n");
exit(1);
}
mid = (*env)->GetStaticMethodID(env, cls, "main", "([Ljava/lang/String
V");
if (mid == 0) {
fprintf(stderr, "Can't find Prog.main\n");
exit(1);
}
jstr = (*env)->NewStringUTF(env, " from C!");
if (jstr == 0) {
fprintf(stderr, "Out of memory\n");
exit(1);
}
args = (*env)->NewObjectArray(env, 1,
(*env)->FindClass(env, "java/lang/String"), jstr);
if (args == 0) {
fprintf(stderr, "Out of memory\n");
exit(1);
}
(*env)->CallStaticVoidMethod(env, cls, mid, args);
(*jvm)->DestroyJavaVM(jvm);
}
2. The Prog.java file :
public class Prog
{
public static void main(
String[] args)
{
System.out.println("Hello World" + args[0]);
}
}
3. On compiling invoke.c using
gcc -D_JNI_IMPLEMENTATION_ -IC:\j2sdk1.4.2\include -IC:\j2sdk1.4.2\include\win32 invoke.c
I'm getting following error.
invoke.c: undefined reference to `JNI_GetDefaultJavaVMInitArgs@4'
invoke.c: undefined reference to `JNI_CreateJavaVM@12'
Can anybody please help me out with this?
