Question

This code is copied directly from http://java.sun.com/docs/books/jni/html/objtypes.html#4013

JNIEXPORT jstring JNICALL 
Java_Prompt_getLine(JNIEnv *env, jobject obj, jstring prompt)
{
    char buf[128];
    const jbyte *str;
    str = (*env)->GetStringUTFChars(env, prompt, NULL);
    if (str == NULL) {
         return NULL; /* OutOfMemoryError already thrown */
    }
     printf("%s", str);
    (*env)->ReleaseStringUTFChars(env, prompt, str);
    /* We assume here that the user does not type more than
     * 127 characters */
    scanf("%s", buf);
    return (*env)->NewStringUTF(env, buf);
}

Why is it neither

env->GetStringUTFChars(...

nor

(*env).GetStringUTFChars(...

?

Answer 1

From earlier in the document you linked in your question:

The first parameter, the JNIEnv interface pointer, points to a location that contains a pointer to a function table

Reading this it seems that JNIEnv is itself a pointer. It’s even a nice picture describing the relationships below the paragraph.