IndexedList ADT Review

Here is the IndexedList ADT from the last chapter:

/**
 * IndexedList ADT.
 */
public interface IndexedList {

  /**
   * Change the value at the given index.
   *
   * @param index representing a position in this list.
   *              Pre: 0 <= index < length
   * @param value to be written at the given index.
   *              Post: this.get(index) == value
   */
  void put(int index, int value);

  /**
   * Retrieve the value stored at the given index.
   *
   * @param index representing a position in this list.
   *              Pre: 0 <= index < length
   * @return value at the given index.
   */
  int get(int index);

  /**
   * Get the declared capacity of this list.
   *
   * @return the length
   *         Inv: length() >= 0
   */
  int length();
}