diff --git a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
index a01ac37..f9b23f0 100644
--- a/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
+++ b/native/jni/com_android_inputmethod_keyboard_ProximityInfo.cpp
@@ -29,18 +29,15 @@
         jint keyCount, jintArray keyXCoordinates, jintArray keyYCoordinates,
         jintArray keyWidths, jintArray keyHeights, jintArray keyCharCodes,
         jfloatArray sweetSpotCenterXs, jfloatArray sweetSpotCenterYs, jfloatArray sweetSpotRadii) {
-    const char *localeCStr = env->GetStringUTFChars(localeJStr, 0);
-    ProximityInfo *proximityInfo = new ProximityInfo(env, localeCStr, maxProximityCharsSize,
+    ProximityInfo *proximityInfo = new ProximityInfo(env, localeJStr, maxProximityCharsSize,
             displayWidth, displayHeight, gridWidth, gridHeight, mostCommonkeyWidth, proximityChars,
             keyCount, keyXCoordinates, keyYCoordinates, keyWidths, keyHeights, keyCharCodes,
             sweetSpotCenterXs, sweetSpotCenterYs, sweetSpotRadii);
-    env->ReleaseStringUTFChars(localeJStr, localeCStr);
     return reinterpret_cast<jlong>(proximityInfo);
 }
 
 static void latinime_Keyboard_release(JNIEnv *env, jobject object, jlong proximityInfo) {
     ProximityInfo *pi = reinterpret_cast<ProximityInfo*>(proximityInfo);
-    if (!pi) return;
     delete pi;
 }
 
diff --git a/native/jni/src/proximity_info.cpp b/native/jni/src/proximity_info.cpp
index 7bae413..4f6507e 100644
--- a/native/jni/src/proximity_info.cpp
+++ b/native/jni/src/proximity_info.cpp
@@ -47,7 +47,7 @@
     }
 }
 
-ProximityInfo::ProximityInfo(JNIEnv *env, const char *localeCStr, const int maxProximityCharsSize,
+ProximityInfo::ProximityInfo(JNIEnv *env, const jstring localeJStr, const int maxProximityCharsSize,
         const int keyboardWidth, const int keyboardHeight, const int gridWidth,
         const int gridHeight, const int mostCommonKeyWidth, const jintArray proximityChars,
         const int keyCount, const jintArray keyXCoordinates, const jintArray keyYCoordinates,
@@ -62,12 +62,16 @@
           KEY_COUNT(min(keyCount, MAX_KEY_COUNT_IN_A_KEYBOARD)),
           HAS_TOUCH_POSITION_CORRECTION_DATA(keyCount > 0 && keyXCoordinates && keyYCoordinates
                   && keyWidths && keyHeights && keyCharCodes && sweetSpotCenterXs
-                  && sweetSpotCenterYs && sweetSpotRadii),
-          mLocaleStr(localeCStr) {
+                  && sweetSpotCenterYs && sweetSpotRadii) {
     const int proximityGridLength = GRID_WIDTH * GRID_HEIGHT * MAX_PROXIMITY_CHARS_SIZE;
     if (DEBUG_PROXIMITY_INFO) {
         AKLOGI("Create proximity info array %d", proximityGridLength);
     }
+    const jsize localeCStrUtf8Length = env->GetStringUTFLength(localeJStr);
+    char localeCStr[localeCStrUtf8Length + 1];
+    env->GetStringUTFRegion(localeJStr, 0, env->GetStringLength(localeJStr), localeCStr);
+    localeCStr[localeCStrUtf8Length] = '\0';
+    mLocaleStr = new std::string(localeCStr);
     mProximityCharsArray = new int32_t[proximityGridLength];
     safeGetOrFillZeroIntArrayRegion(env, proximityChars, proximityGridLength, mProximityCharsArray);
     safeGetOrFillZeroIntArrayRegion(env, keyXCoordinates, KEY_COUNT, mKeyXCoordinates);
@@ -94,6 +98,7 @@
 }
 
 ProximityInfo::~ProximityInfo() {
+    delete mLocaleStr;
     delete[] mProximityCharsArray;
 }
 
@@ -166,7 +171,7 @@
             }
         }
         const int additionalProximitySize =
-                AdditionalProximityChars::getAdditionalCharsSize(&mLocaleStr, primaryKey);
+                AdditionalProximityChars::getAdditionalCharsSize(mLocaleStr, primaryKey);
         if (additionalProximitySize > 0) {
             inputCodes[insertPos++] = ADDITIONAL_PROXIMITY_CHAR_DELIMITER_CODE;
             if (insertPos >= MAX_PROXIMITY_CHARS_SIZE) {
@@ -177,7 +182,7 @@
             }
 
             const int32_t *additionalProximityChars =
-                    AdditionalProximityChars::getAdditionalChars(&mLocaleStr, primaryKey);
+                    AdditionalProximityChars::getAdditionalChars(mLocaleStr, primaryKey);
             for (int j = 0; j < additionalProximitySize; ++j) {
                 const int32_t ac = additionalProximityChars[j];
                 int k = 0;
diff --git a/native/jni/src/proximity_info.h b/native/jni/src/proximity_info.h
index 5dd378d..7222d0d 100644
--- a/native/jni/src/proximity_info.h
+++ b/native/jni/src/proximity_info.h
@@ -29,7 +29,7 @@
 
 class ProximityInfo {
  public:
-    ProximityInfo(JNIEnv *env, const char *localeCStr, const int maxProximityCharsSize,
+    ProximityInfo(JNIEnv *env, const jstring localeJStr, const int maxProximityCharsSize,
             const int keyboardWidth, const int keyboardHeight, const int gridWidth,
             const int gridHeight, const int mostCommonKeyWidth, const jintArray proximityChars,
             const int keyCount, const jintArray keyXCoordinates, const jintArray keyYCoordinates,
@@ -76,7 +76,7 @@
     }
 
     std::string getLocaleStr() const {
-        return mLocaleStr;
+        return *mLocaleStr;
     }
 
     int getKeyCount() const {
@@ -129,7 +129,7 @@
     const int CELL_HEIGHT;
     const int KEY_COUNT;
     const bool HAS_TOUCH_POSITION_CORRECTION_DATA;
-    const std::string mLocaleStr;
+    const std::string *mLocaleStr;
     int32_t *mProximityCharsArray;
     int32_t mKeyXCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
     int32_t mKeyYCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];