Here is how to create process and Image APPName.exe file instead of java or javaw

[Pratap koritala]

Hi,
I am not talking about how to write kicker ( small c program that will create a new process with java.exe with parameters like java.exe -jar somejar.jar )

Ex: if you execute netbeans.exe(small kicker), it just starts another process with java.exe (try killing netbeans.exe ,your IDE still works)


I used to wondered,"How come eclipse.exe managed to embedded JVM with in its process(it won't create another process,unless it didn't find shared JVM)..."

I downloaded Eclipse Source,but its not much clear.
Here's much cleaner code. ( If you observe the code ,you can find much intresting things....)

 
#include <jni.h>
 
 #define PATH_SEPARATOR ';' /* define it to be ':' on Solaris */
 #define USER_CLASSPATH "." /* where HelloWorld.class is */
 
 main() {
     JNIEnv *env;
     JavaVM *jvm;
     jint res;
     jclass cls;
     jmethodID mid;
     jstring jstr;
     jclass stringClass;
     jobjectArray args;
 
 #ifdef JNI_VERSION_1_2
     JavaVMInitArgs vm_args;
     JavaVMOption options[1];
     options[0].optionString =
         "-Djava.class.path=" USER_CLASSPATH;
     vm_args.version = 0x00010002;
     vm_args.options = options;
     vm_args.nOptions = 1;
     vm_args.ignoreUnrecognized = JNI_TRUE;
     /* Create the Java VM */
     res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
 #else
     JDK1_1InitArgs vm_args;
     char classpath[1024];
     vm_args.version = 0x00010001;
     JNI_GetDefaultJavaVMInitArgs(&vm_args);
     /* Append USER_CLASSPATH to the 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, &env, &vm_args);
 #endif /* JNI_VERSION_1_2 */
 
     if (res < 0) {
         fprintf(stderr, "Can't create Java VM\n");
         exit(1);
     }
     cls = (*env)->FindClass(env, "HelloWorld");
     if (cls == NULL) {
         goto destroy;
     }
 
     mid = (*env)->GetStaticMethodID(env, cls, "main",
                                     "([Ljava/lang/String ; ) V");
     if (mid == NULL) {
         goto destroy;
     }
     jstr = (*env)->NewStringUTF(env, " from C!");
     if (jstr == NULL) {
         goto destroy;
     }
     stringClass = (*env)->FindClass(env, "java/lang/String");
     args = (*env)->NewObjectArray(env, 1, stringClass, jstr);
     if (args == NULL) {
         goto destroy;
     }
     (*env)->CallStaticVoidMethod(env, cls, mid, args);
 
 destroy:
     if ((*env)->ExceptionOccurred(env)) {
         (*env)->ExceptionDescribe(env);
     }
     (*jvm)->DestroyJavaVM(jvm);
 }
 

 
public class HelloWorld 
{
     public static void main(String[] args) 
     {
          System.out.println("Hello World " + args[0]);
     }
}

[ July 28, 2008: Message edited by: Pratap koritala ]