Fix for Random Pin Callback

Need to ensure thread was attached and CallVoidMethod().

Change-Id: I0b3e6fb2a281eccd7b02ba173b5aef0b20919210
Signed-off-by: Larry Sachs <larry.j.sachs@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/29431Tested-by: IoTivity Jenkins <jenkins-daemon@iotivity.org>
Reviewed-by: George Nash <george.nash@intel.com>
Reviewed-by: Rick Bell <richard.s.bell@intel.com>

swig/swig_interfaces/oc_api.i

@@ -488,6 +488,8 @@ void jni_oc_random_pin_callback(const unsigned char *pin, size_t pin_len, void *
 {
   OC_DBG("JNI: %s\n", __func__);
   jni_callback_data *data = (jni_callback_data *)user_data;
+  jint getEnvResult = 0;
+  data->jenv = GetJNIEnv(&getEnvResult);
 
   assert(cls_OCRandomPinHandler);
   const jmethodID mid_handler = JCALL3(GetMethodID,
@@ -498,9 +500,9 @@ void jni_oc_random_pin_callback(const unsigned char *pin, size_t pin_len, void *
   assert(mid_handler);
 
   jstring jpin = JCALL1(NewStringUTF, (data->jenv), (const char *)pin);
+  JCALL3(CallVoidMethod, (data->jenv), data->jcb_obj, mid_handler, jpin);
 
-  /* TODO convert pin to java string */
-  JCALL3(CallObjectMethod, (data->jenv), data->jcb_obj, mid_handler, jpin);
+  ReleaseJNIEnv(getEnvResult);
 }
 %}