所有 Java 方法调用返回值类型 :
jobject (*CallObjectMethod)(JNIEnv*, jobject, jmethodID, ...);
jobject...(*CallObjectMethodV)(JNIEnv*, jobject, jmethodID, va_list);
jobject (*CallObjectMethodA)...(JNIEnv*, jobject, jmethodID, const jvalue*);
jboolean (*CallBooleanMethod)(JNIEnv*, jobject,...)(JNIEnv*, jobject, jmethodID, ...);
jbyte (*CallByteMethodV)(JNIEnv*, jobject, jmethodID,...*, jobject, jmethodID, ...);
jdouble (*CallDoubleMethodV)(JNIEnv*, jobject, jmethodID, va_list