diff --git a/lsplant/src/main/jni/include/utils/jni_helper.hpp b/lsplant/src/main/jni/include/utils/jni_helper.hpp
index 4077607..9adf5c6 100644
--- a/lsplant/src/main/jni/include/utils/jni_helper.hpp
+++ b/lsplant/src/main/jni/include/utils/jni_helper.hpp
@@ -792,11 +792,6 @@ template <typename U, typename T>
 template <JArray T>
 struct JArrayUnderlyingTypeHelper;
 
-template <>
-struct JArrayUnderlyingTypeHelper<jobjectArray> {
-    using Type = ScopedLocalRef<jobject>;
-};
-
 template <>
 struct JArrayUnderlyingTypeHelper<jbooleanArray> {
     using Type = jboolean;
@@ -1053,6 +1048,246 @@ private:
     DISALLOW_COPY_AND_ASSIGN(ScopedLocalRef);
 };
 
+
+class JObjectArrayElement{
+public:
+    friend class ScopedLocalRef<jobjectArray>;
+    explicit JObjectArrayElement(JNIEnv * env, jobjectArray array, int i) : env_(env), array_(array), i_(i) {
+        item_ = JNI_SafeInvoke(env_, &JNIEnv::GetObjectArrayElement, array_, i_).release();
+    }
+
+    ~JObjectArrayElement(){
+        if (item_){
+            env_->DeleteLocalRef(item_);
+        }
+    }
+
+    void reset(int i){
+        if (item_){
+            env_->DeleteLocalRef(item_);
+        }
+        i_ = i;
+        item_ = JNI_SafeInvoke(env_, &JNIEnv::GetObjectArrayElement, array_, i).release();
+    }
+
+    JObjectArrayElement(JObjectArrayElement&& s){
+        env_ = s.env_;
+        array_ = s.array_;
+        i_ = s.i_;
+        item_ = s.item_;
+        s.env_ = nullptr;
+        s.array_ = nullptr;
+        s.i_ = -1;
+        s.item_ = nullptr;
+    }
+
+    operator jobject(){
+        return item_;
+    }
+
+    JObjectArrayElement &operator=(jobject s) noexcept {
+        if (item_){
+            env_->DeleteLocalRef(item_);
+        }
+        JNI_SafeInvoke(env_, &JNIEnv::SetObjectArrayElement, array_, i_, s);
+        item_ = s;
+        return *this;
+    }
+private:
+    JNIEnv *env_;
+    jobjectArray array_;
+    int i_;
+    jobject item_;
+    DISALLOW_COPY_AND_ASSIGN(JObjectArrayElement);
+};
+
+template<>
+class ScopedLocalRef<jobjectArray> {
+    using T = jobjectArray;
+
+    ScopedLocalRef(JNIEnv *env, T local_ref, size_t size,bool modified) noexcept
+            : env_(env), local_ref_(local_ref), size_(size), modified_(modified) {}
+
+public:
+    class Iterator {
+        friend class ScopedLocalRef<T>;
+
+        Iterator(JObjectArrayElement&& e) : e_(std::move(e)) {}
+
+        JObjectArrayElement e_;
+
+    public:
+        auto &operator*() { return e_; }
+
+        auto *operator->() { return &e_; }
+
+        Iterator &operator++() {
+            e_.reset(e_.i_ + 1);
+            return *this;
+        }
+
+        Iterator &operator--() {
+            e_.reset(e_.i_ - 1);
+            return *this;
+        }
+
+        Iterator operator++(int) {
+            return Iterator(JObjectArrayElement(e_.env_, e_.array_, e_.i_ + 1));
+        }
+
+        Iterator operator--(int) {
+            return Iterator(JObjectArrayElement(e_.env_, e_.array_, e_.i_ - 1));
+        }
+
+        bool operator==(const Iterator &other) const { return other.e_.i_ == e_.i_; }
+
+        bool operator!=(const Iterator &other) const { return other.e_.i_ != e_.i_; }
+    };
+
+//    class ConstIterator {
+//        friend class ScopedLocalRef<T>;
+//
+//        ConstIterator(int i) : i_(i) {
+//            item_ = JNI_SafeInvoke(env_, &JNIEnv::GetObjectArrayElement, local_ref_, i);
+//        }
+//
+//        int i_;
+//        jobject item_;
+//
+//    public:
+//        auto &operator*() { return e_; }
+//
+//        auto *operator->() { return &e_; }
+//
+//        ConstIterator &operator++() {
+//            e_ = std::move(JObjectArrayConstElement(e_.env_, e_.array_, e_.i_ + 1));
+//            return *this;
+//        }
+//
+//        ConstIterator &operator--() {
+//            e_ = JObjectArrayConstElement(e_.env_, e_.array_, e_.i_ - 1);
+//            return *this;
+//        }
+//
+//        ConstIterator operator++(int) {
+//            return ConstIterator(JObjectArrayConstElement(e_.env_, e_.array_, e_.i_ + 1));
+//        }
+//
+//        ConstIterator operator--(int) {
+//            return ConstIterator(JObjectArrayConstElement(e_.env_, e_.array_, e_.i_ - 1));
+//        }
+//
+//        bool operator==(const ConstIterator &other) const { return other.e_.i_ == e_.i_; }
+//
+//        bool operator!=(const ConstIterator &other) const { return other.e_.i_ != e_.i_; }
+//    };
+
+    auto begin() {
+        modified_ = true;
+        return Iterator(JObjectArrayElement(env_, local_ref_, 0));
+    }
+
+    auto end() {
+        modified_ = true;
+        return Iterator(JObjectArrayElement(env_, local_ref_, size_));
+    }
+
+//    const auto begin() const { return ConstIterator(JObjectArrayConstElement(env_, local_ref_, 0)); }
+//
+//    auto end() const { return ConstIterator(JObjectArrayConstElement(env_, local_ref_, size_)); }
+//
+//    const auto cbegin() const { return ConstIterator(JObjectArrayConstElement(env_, local_ref_, 0)); }
+//
+//    auto cend() const { return ConstIterator(JObjectArrayConstElement(env_, local_ref_, size_)); }
+
+    using BaseType [[maybe_unused]] = T;
+
+    ScopedLocalRef(JNIEnv *env, T local_ref) noexcept: env_(env), local_ref_(nullptr) {
+        reset(local_ref);
+    }
+
+    ScopedLocalRef(ScopedLocalRef &&s) noexcept
+            : ScopedLocalRef(s.env_, s.local_ref_, s.size_, s.modified_) {
+            s.local_ref_ = nullptr;
+            s.size_ = 0;
+            s.modified_ = false;
+    }
+
+    template<JObject U>
+    ScopedLocalRef(ScopedLocalRef<U> &&s) noexcept : ScopedLocalRef(s.env_, (T) s.release()) {}
+
+    explicit ScopedLocalRef(JNIEnv *env) noexcept: ScopedLocalRef(env, T{nullptr}) {}
+
+    ~ScopedLocalRef() { env_->DeleteLocalRef(release()); }
+
+    void reset(T ptr = nullptr) {
+        if (ptr != local_ref_) {
+            if (local_ref_ != nullptr) {
+                env_->DeleteLocalRef(local_ref_);
+            }
+            local_ref_ = ptr;
+            size_ = local_ref_ ? env_->GetArrayLength(local_ref_) : 0;
+            if (!local_ref_) return;
+        }
+    }
+
+    [[nodiscard]] T release() {
+        T localRef = local_ref_;
+        size_ = 0;
+        local_ref_ = nullptr;
+        return localRef;
+    }
+
+    T get() const { return local_ref_; }
+
+    explicit operator T() const { return local_ref_; }
+
+    JObjectArrayElement operator[](size_t index) {
+        modified_ = true;
+        return JObjectArrayElement(env_, local_ref_, index);
+    }
+
+    const ScopedLocalRef<jobject> operator[](size_t index) const {
+        return JNI_SafeInvoke(env_, &JNIEnv::GetObjectArrayElement, local_ref_, index);
+    }
+
+    void commit() {
+        modified_ = false;
+    }
+
+    // We do not expose an empty constructor as it can easily lead to errors
+    // using common idioms, e.g.:
+    //   ScopedLocalRef<...> ref;
+    //   ref.reset(...);
+    // Move assignment operator.
+    ScopedLocalRef &operator=(ScopedLocalRef &&s) noexcept {
+        env_ = s.env_;
+        local_ref_ = s.local_ref_;
+        size_ = s.size_;
+        modified_ = s.modified_;
+        s.size_ = 0;
+        s.modified_ = false;
+        s.local_ref_ = nullptr;
+        return *this;
+    }
+
+    size_t size() const { return size_; }
+
+    operator bool() const { return local_ref_; }
+
+    template<JObject U>
+    friend
+    class ScopedLocalRef;
+
+    friend class JUTFString;
+
+private:
+    JNIEnv *env_;
+    T local_ref_;
+    size_t size_;
+    bool modified_ = false;
+    DISALLOW_COPY_AND_ASSIGN(ScopedLocalRef);
+};
 // functions to array
 
 template <ScopeOrRaw<jarray> Array>