Java collection framework List

The Java collection framework provides an Listinterface for storing an ordered set of elements. ListElements in are repeatable and can be accessed by index. If you are familiar with arrays, you can Listthink of them as a kind of dynamic array.

ListInterfaces have many implementation classes, some of the more common ones include:

• ArrayList: Based on a dynamic array implementation, the search and access speeds are fast, and the insertion and deletion speeds are relatively slow;
• LinkedList: Based on linked list implementation, insertion and deletion are fast, but access speed is slow;
• Vector: ArrayListSimilar to, but thread-safe, so it is safer to use in a multi-threaded environment;
• Stack: Inherited from Vector, provides last-in-first-out (LIFO) stack structure.

ListThe interface defines the methods to operate on the list, commonly used include:

• add(E e): Adds an element to the end of the list.
• get(int index): Returns the element at the specified position.
• remove(int index): Remove the element at the specified position.
• size(): Returns the number of elements in the list.

In addition to these basic operations, Listsome other operations are provided, such as sorting, searching, sublisting, etc. These operations can be implemented through the methods of Collectionsthe class or Listinterface itself.

In short, Listit is a very important and commonly used type in the Java collection framework, which can easily manage and operate a set of ordered data.

The Java collection framework provides an Listinterface for storing an ordered set of elements. ListElements in can be repeated and can be accessed by subscript. If you are familiar with arrays, you can think Listof them as a dynamic array.

Here is a simple example showing how to create one Listand add elements:

javaCopy code

import java.util.ArrayList; import java.util.List; public class Main { public static void main(String[] args) { List<String> list = new ArrayList<>(); list.add("apple"); list.add("banana"); list.add("orange"); System.out.println(list); } }

This program will output: [apple, banana, orange].

Note that Listit is an interface and cannot be instantiated directly. In the above example, we used ArrayListclasses to implement Listinterfaces.

ListThe interface provides many methods to manipulate lists. Here are some commonly used methods:

• add(E e) - Adds an element to the end of the list.
• get(int index) - Returns the element at the specified position.
• remove(int index) - Removes the element at the specified position.
• size() - Returns the number of elements in the list.