如何使用JNI在Builder C ++应用程序中启动JVM

Question

So i need to use jni to call java method. i started with this code :

JNIEnv *env1;
JavaVM**  jvm1;
JavaVMInitArgs vm_args1;
JavaVMOption options1[1];
options1[0].optionString = "-Djava.class.path=D:\\Java Src\\TestStruct"; //Path to the java source code
vm_args1.version = JNI_VERSION_1_6; //JDK version. This indicates version 1.6
vm_args1.nOptions = 1;
vm_args1.options = options1;
vm_args1.ignoreUnrecognized = 0;

int reAt = JNI_CreateJavaVM(jvm1, (void**)&env1, &vm_args1);
if(reAt < 0)
    Label1->Caption = "failed";
else
    Label1->Caption = "Success";

I convert jvm.lib to OMF lib for to use in my builder C++ Application :

 COFF2OMF jvm.lib jvm2.lib

I added jvm2.lib to the library path to fixe link error about JNI_CreateJavaVM function.

Now my application compile without error.

But it crash when it call JNI_CreateJavaVM function.

I added the jvm.dll near my .exe

What is the pb in there steps??

How can fixe it?

Thx

Answer 1

The first argument to JNI_CreateJavaVM should be a valid pointer to JavaVM* :

JavaVM* jvm1;
int reAt = JNI_CreateJavaVM(&jvm1, ...);

In your example, jvm1 is uninitialized.

Consult the documentation for details.