diff --git a/native/jni/src/proximity_info_state.cpp b/native/jni/src/proximity_info_state.cpp
index 387b03a24..141be2688 100644
--- a/native/jni/src/proximity_info_state.cpp
+++ b/native/jni/src/proximity_info_state.cpp
@@ -27,8 +27,6 @@
 
 namespace latinime {
 
-const int ProximityInfoState::NOT_A_CODE = -1;
-
 void ProximityInfoState::initInputParams(const int pointerId, const float maxPointToKeyLength,
         const ProximityInfo *proximityInfo, const int *const inputCodes, const int inputSize,
         const int *const xCoordinates, const int *const yCoordinates, const int *const times,
diff --git a/native/jni/src/proximity_info_state.h b/native/jni/src/proximity_info_state.h
index 7422cb08f..ff1b35089 100644
--- a/native/jni/src/proximity_info_state.h
+++ b/native/jni/src/proximity_info_state.h
@@ -32,9 +32,6 @@ class ProximityInfo;
 
 class ProximityInfoState {
  public:
-
-    static const int NOT_A_CODE;
-
     /////////////////////////////////////////
     // Defined in proximity_info_state.cpp //
     /////////////////////////////////////////
@@ -196,6 +193,7 @@ class ProximityInfoState {
             const int from, const int to, const int keyId, const bool extend) const;
 
     bool isKeyInSerchKeysAfterIndex(const int index, const int keyId) const;
+
  private:
     DISALLOW_COPY_AND_ASSIGN(ProximityInfoState);
     /////////////////////////////////////////
diff --git a/native/jni/src/suggest_utils.h b/native/jni/src/suggest_utils.h
index 7d49cde7e..aab9f7ba8 100644
--- a/native/jni/src/suggest_utils.h
+++ b/native/jni/src/suggest_utils.h
@@ -19,7 +19,6 @@
 
 #include "defines.h"
 #include "proximity_info_params.h"
-#include "proximity_info_state.h"
 
 namespace latinime {
 class SuggestUtils {
diff --git a/native/jni/src/words_priority_queue.h b/native/jni/src/words_priority_queue.h
index 7aab1e083..e0833ce4b 100644
--- a/native/jni/src/words_priority_queue.h
+++ b/native/jni/src/words_priority_queue.h
@@ -110,7 +110,7 @@ class WordsPriorityQueue {
         }
     }
 
-    AK_FORCE_INLINE void dumpTopWord() {
+    AK_FORCE_INLINE void dumpTopWord() const {
         if (size() <= 0) {
             return;
         }
@@ -118,7 +118,7 @@ class WordsPriorityQueue {
     }
 
     AK_FORCE_INLINE float getHighestNormalizedScore(const int *before, const int beforeLength,
-            int **outWord, int *outScore, int *outLength) {
+            int **outWord, int *outScore, int *outLength) const {
         if (!mHighestSuggestedWord) {
             return 0.0f;
         }
@@ -137,7 +137,7 @@ class WordsPriorityQueue {
         }
     };
 
-    SuggestedWord *getFreeSuggestedWord(int score, int *word, int wordLength, int type) {
+    SuggestedWord *getFreeSuggestedWord(int score, int *word, int wordLength, int type) const {
         for (int i = 0; i < MAX_WORD_LENGTH; ++i) {
             if (!mSuggestedWords[i].mUsed) {
                 mSuggestedWords[i].setParams(score, word, wordLength, type);
diff --git a/native/jni/src/words_priority_queue_pool.h b/native/jni/src/words_priority_queue_pool.h
index cfe7ede63..2cd210a05 100644
--- a/native/jni/src/words_priority_queue_pool.h
+++ b/native/jni/src/words_priority_queue_pool.h
@@ -44,11 +44,11 @@ class WordsPriorityQueuePool {
         }
     }
 
-    WordsPriorityQueue *getMasterQueue() {
+    WordsPriorityQueue *getMasterQueue() const {
         return mMasterQueue;
     }
 
-    WordsPriorityQueue *getSubQueue(const int wordIndex, const int inputWordLength) {
+    WordsPriorityQueue *getSubQueue(const int wordIndex, const int inputWordLength) const {
         if (wordIndex >= MULTIPLE_WORDS_SUGGESTION_MAX_WORDS) {
             return 0;
         }
@@ -77,7 +77,7 @@ class WordsPriorityQueuePool {
         }
     }
 
-    void dumpSubQueue1TopSuggestions() {
+    void dumpSubQueue1TopSuggestions() const {
         AKLOGI("DUMP SUBQUEUE1 TOP SUGGESTIONS");
         for (int i = 0; i < SUB_QUEUE_MAX_COUNT; ++i) {
             getSubQueue(0, i)->dumpTopWord();