diff --git a/api/@ohos.buffer.d.ts b/api/@ohos.buffer.d.ts
index 1627e06e8ecab0f4b9adc718e136057defdc8b25..d3cca26d7e5b217d7fec342a2fe6e1332c1b0b88 100644
--- a/api/@ohos.buffer.d.ts
+++ b/api/@ohos.buffer.d.ts
@@ -3551,30 +3551,20 @@ declare namespace buffer {
     writeUIntLE(value: number, offset: number, byteLength: number): number;
 
     /**
-     * Returns the byte at the specified index.
+     * Returns the item at that index.
      *
-     * @param { number } index - byte index to read
-     * @returns { number | undefined } Returns the byte value at `index`
+     * @param { number } index - The zero-based index of the desired code unit.
+     *     Throws error if index < 0 or index >= buffer.length.
+     * @returns { number } The element in the buffer matching the given index. 
+     * @throws { BusinessError } 10200001 - The value of index is out of range.
      * @syscap SystemCapability.Utils.Lang
      * @crossplatform
      * @atomicservice
      * @since 20
      * @arkts 1.2
      */
-    $_get(index: number): number | undefined;
+    [index: number]: number;
 
-    /**
-     * Sets the byte at the specified index.
-     *
-     * @param { number } index – byte index to write
-     * @param { number } value – byte value (0–255)
-     * @syscap SystemCapability.Utils.Lang
-     * @crossplatform
-     * @atomicservice
-     * @since 20
-     * @arkts 1.2
-     */
-    $_set(index: number, value: number): void;
   }
 
   /**
diff --git a/api/@ohos.util.ArrayList.d.ts b/api/@ohos.util.ArrayList.d.ts
index 55f957b50b620dc25299198c6f53b6d1a5c588c5..23618e27f5b3ff755c5ca3bdc132e2855bcb8970 100644
--- a/api/@ohos.util.ArrayList.d.ts
+++ b/api/@ohos.util.ArrayList.d.ts
@@ -800,37 +800,13 @@ declare class ArrayList<T> {
    * @throws { BusinessError } 401 - Parameter error.
    * @throws { BusinessError } 10200001 - The value of index is out of range.
    * @syscap SystemCapability.Utils.Lang
+   * @crossplatform
    * @atomicservice
-   * @since 12
+   * @since arkts {'1.1':'12', '1.2':'20'}
+   * @arkts 1.1&1.2
    */
   [index: number]: T;
 
-  /**
-   * Returns the item at that index.
-   * 
-   * @param { number } index - The zero-based index of the desired code unit.
-   * @returns { T } The element in the arrayList matching the given index.
-   * @throws { BusinessError } 10200001 - The value of index is out of range.
-   * @syscap SystemCapability.Utils.Lang
-   * @atomicservice
-   * @since 20
-   * @arkts 1.2
-   */
-  $_get(index: number): T;
-
-  /**
-   * Set the value of item at that index.
-   *
-   * @param { number } index - The index of the element to set.
-   * @param { T } value - The value to set at the specified index.
-   * @throws { BusinessError } 10200001 - The value of index is out of range.
-   * @syscap SystemCapability.Utils.Lang
-   * @atomicservice
-   * @since 20
-   * @arkts 1.2
-   */
-  $_set(index: number, value: T): void;
-
   /**
    * If the newCapacity provided by the user is greater than or equal to length,
    * change the capacity of the arraylist to newCapacity, otherwise the capacity will not be changed
diff --git a/api/@ohos.util.Deque.d.ts b/api/@ohos.util.Deque.d.ts
index 73f2f662e3e75fece772966d2acfe7056bf6af27..ddf7fcb85cf663b117e28d3067d3421d3bac51d9 100644
--- a/api/@ohos.util.Deque.d.ts
+++ b/api/@ohos.util.Deque.d.ts
@@ -427,31 +427,21 @@ declare class Deque<T> {
    * @arkts 1.2
    */
   forEach(callbackFn: DequeForEachCb<T>): void;
-  /**
-   * Returns the byte at the specified index.
-   *
-   * @param { number } index - The zero-based index of the desired code unit.
-   * @returns { T } The element in the deque matching the given index.
-   * @syscap SystemCapability.Utils.Lang
-   * @crossplatform
-   * @atomicservice
-   * @since 20
-   * @arkts 1.2
-   */
-  $_get(index: number): T;
 
-  /**
-   * Sets the byte at the specified index.
-   *
-   * @param { number } index – The index of the element to set.
-   * @param { T } value – The value to set at the specified index.
+   /**
+   * Returns the item at that index.
+   * 
+   * @param { number } index - The zero-based index of the desired code unit.
+   *     Throws error if index < 0 or index >= deque.length.
+   * @returns { T } The element in the deque matching the given index. 
+   * @throws { BusinessError } 10200001 - The value of index is out of range.
    * @syscap SystemCapability.Utils.Lang
    * @crossplatform
    * @atomicservice
    * @since 20
    * @arkts 1.2
    */
-  $_set(index: number, value: T): void;
+  [index: number]: T;
 
   /**
    * returns an iterator.Each item of the iterator is a Javascript Object
diff --git a/api/@ohos.util.List.d.ts b/api/@ohos.util.List.d.ts
index 405a412252cbb04e256a5274e86c9b5af6a78f0a..d462a06f10171a6f87249e5b195ddd4cc474340e 100644
--- a/api/@ohos.util.List.d.ts
+++ b/api/@ohos.util.List.d.ts
@@ -925,32 +925,22 @@ declare class List<T> {
    * @arkts 1.1&1.2
    */
   isEmpty(): boolean;
-  /**
-   * Returns the item at that index
-   *
-   * @param { number } index - the zero-based index of the desired code unit.
-   * @returns { T | undefined } the element in the list matching the given index,
-   * or undefined if the index is out of range.
-   * @syscap SystemCapability.Utils.Lang
-   * @crossplatform
-   * @atomicservice
-   * @since 20
-   * @arkts 1.2
-   */
-  $_get(index: number): T | undefined;
 
   /**
-   * Set the value of item at that index.
-   *
-   * @param { number } index – the index of the element to set.
-   * @param { T } value – the value to set at the specified index
+   * Returns the item at that index.
+   * 
+   * @param { number } index - The zero-based index of the desired code unit.
+   *     Throws error if index < 0 or index >= list.length.
+   * @returns { T } The element in the list matching the given index. 
+   * @throws { BusinessError } 10200001 - The value of index is out of range.
    * @syscap SystemCapability.Utils.Lang
    * @crossplatform
    * @atomicservice
    * @since 20
    * @arkts 1.2
    */
-  $_set(index: number, value: T): void;
+  [index: number]: T;
+
   /**
    * returns an iterator.Each item of the iterator is a Javascript Object
    *
diff --git a/arkts/@arkts.collections.d.ets b/arkts/@arkts.collections.d.ets
index f8127b775b4e2473e7f75e8417409d4f3245723d..11b52769f0892af7d013325a4ca4c1a0607109a7 100644
--- a/arkts/@arkts.collections.d.ets
+++ b/arkts/@arkts.collections.d.ets
@@ -11971,30 +11971,22 @@ declare namespace collections {
      * @arkts 1.2
      */
     values(): IterableIterator<number>;
+
     /**
      * Returns the item at that index.
      * 
      * @param { number } index - The zero-based index of the desired code unit.
-     * @returns { number } The element in the bitVector matching the given index.
+     *     Throws error if index < 0 or index >= bitVector.length.
+     * @returns { number } The element in the bitVector matching the given index. 
+     * @throws { BusinessError } 10200001 - The value of index is out of range.
      * @syscap SystemCapability.Utils.Lang
      * @crossplatform
      * @atomicservice
      * @since 20
      * @arkts 1.2
      */
-    $_get(index: number): number;
-    /**
-     * Set the value of item at that index.
-     *
-     * @param { number } index - The index of the element to set.
-     * @param { number } value - The value to set at the specified index.
-     * @syscap SystemCapability.Utils.Lang
-     * @atomicservice
-     * @crossplatform
-     * @since 20
-     * @arkts 1.2
-     */
-    $_set(index: number, value: number): void;
+    [index: number]: number;    
+     
   }
 
   /**