JNI: Create HashMap

Question

How do I create a HashMap object in JNI?

Answer 1

See here:

Some example code to call a String constructor:

jstring
 MyNewString(JNIEnv *env, jchar *chars, jint len)
 {
     jclass stringClass;
     jmethodID cid;
     jcharArray elemArr;
     jstring result;

     stringClass = (*env)->FindClass(env, "java/lang/String");
     if (stringClass == NULL) {
         return NULL; /* exception thrown */
     }
 /* Get the method ID for the String(char[]) constructor */
     cid = (*env)->GetMethodID(env, stringClass,
                               "", "([C)V");
     if (cid == NULL) {
         return NULL; /* exception thrown */
     }

     /* Create a char[] that holds the string characters */
     elemArr = (*env)->NewCharArray(env, len);
     if (elemArr == NULL) {
         return NULL; /* exception thrown */
     }
     (*env)->SetCharArrayRegion(env, elemArr, 0, len, chars);

     /* Construct a java.lang.String object */
     result = (*env)->NewObject(env, stringClass, cid, elemArr);

     /* Free local references */
     (*env)->DeleteLocalRef(env, elemArr);
     (*env)->DeleteLocalRef(env, stringClass);
     return result;
 }