Java List Interface

In Java, List is an interface and which is an order collection also List is use to store and access elements sequentially. List interface available in java.util package. List can have duplicate elements also it will store null elements in the List.
There are 4 different classes in List interface.

  1. i. ArrayList
  2. ii. LinkedList
  3. iii. Vector
  4. iv. Stack

Methods of List Interface

List interface contains some use full methods those are below:

  1. ◈ add(int index, element): This method is used to add an element at a particular index in the list. When a single parameter is passed, it simply adds the element at the end of the list.
  2. ◈ addAll(int index, Collection collection): This method is used to add all the elements in the given collection to the list. When a single parameter is passed, it adds all the elements of the given collection at the end of the list.
  3. ◈ size(): This method is used to return the size of the list.
  4. ◈ clear(): This method is used to remove all the elements in the list. However, the reference of the list created is still stored.
  5. ◈ remove(int index): This method removes an element from the specified index. It shifts subsequent elements(if any) to left and decreases their indexes by 1.
  6. ◈ remove(element): This method is used to remove the first occurrence of the given element in the list.
  7. ◈ get(int index): This method returns elements at the specified index.
  8. ◈ set(int index, element): This method replaces elements at a given index with the new element. This function returns the element which was just replaced by a new element.
  9. ◈ indexOf(element): This method returns the first occurrence of the given element or -1 if the element is not present in the list.
  10. ◈ lastIndexOf(element): This method returns the last occurrence of the given element or -1 if the element is not present in the list.
  11. ◈ equals(element): This method is used to compare the equality of the given element with the elements of the list.
  12. ◈ hashCode(): This method is used to return the hashcode value of the given list.
  13. ◈ isEmpty(): This method is used to check if the list is empty or not. It returns true if the list is empty, else false.
  14. ◈ contains(element): This method is used to check if the list contains the given element or not. It returns true if the list contains the element.
  15. ◈ containsAll(Collection collection): This method is used to check if the list contains all the collection of elements.
  16. ◈ sort(Comparator comp): This method is used to sort the elements of the list on the basis of the given comparator.