Question

How to deliver a string array?

I post the code:

xx.cpp

JNIEXPORT jstring JNICALL Hello_Native(JNIEnv *env, jobject obj,jstring string)
{
    const char *str = env->GetStringUTFChars(string, 0);
    return env->NewStringUTF( "Hello from JNI !");
}
static JNINativeMethod gMethods[] = {
   {"JniHello",const_cast<char*>("(Ljava/lang/jsting)Ljava/lang/jsting;"),(void*)Hello_Native}

xx.java

public native static String JniHello(String text);

System always prompt it has the problem when declare JniHello in gMethods and the parameter is not right.

Answer 1

1. stop using wrong manual names for JNICALL functions. javah will generate it for you correctly. If your Java name is JniHello in class MyHello and your package is com.hello , JNICALL function must be Java_com_hello_MyHello_JniHello. It can’t be Hello_Native, you have made it up.
2. then of course this correct function name must be used in the last member of JNINativeMethod struct
3. there is no such class as java/lang/jsting. There is not even a java/lang/jstring if i add the missing r for you. You are asked for the JAVA signature, not JNI. So it must be java/lang/String.
4. ADDED (thanks @EJP): stop using wrong manual strings for JNI signatures and use the output of javap -s instead

Your code has one more problem: when used GetStringUTFChars, you must also call `ReleaseStringUTFChars’ before returning, otherwise you have a leak. But you will find this yourself sooner or later.