Detailed explanation of List in Apache Commons Collection

Apache Commons Collections is an open source Java class library, which aims to enhance the function of the standard Java collection class.It provides many expansion functions that make the processing set more convenient and efficient.In Apache Commons Collections, List is a common collection type that allows storage to store orderly and repeated elements.The List interface provides a series of methods for operating elements and provides multiple implementation classes to meet different needs.This article will introduce the List implementation in Apache Commons Collections. In Apache Commons Collections, the main implementation classes of the List interface include ArrayList, LinkedList, Treelist, and Cowallist. 1. ArrayList ArrayList is a List based on array, which provides the ability to access the elements randomly, which can obtain elements at the specified index at a constant time.ArrayList also supports dynamic expansion, which can automatically adjust the capacity as needed.The following is an example code of ArrayList: List<String> arrayList = new ArrayList<>(); arrayList.add("Apple"); arrayList.add("Banana"); arrayList.add("Orange"); System.out.println(arrayList); 2. LinkedList LinkedList is a List based on a two -way linked list, which provides the ability to quickly add and delete elements.Unlike ArrayList, LinkedList does not need to move other elements when inserting and deleting elements, so it may be more efficient in some application scenarios.The following is the example code of LinkedList: List<String> linkedList = new LinkedList<>(); linkedList.add("Apple"); linkedList.add("Banana"); linkedList.add("Orange"); System.out.println(linkedList); 3. TreeList Treelist is a List -based implementation of tree structure, which stores elements in an orderly state and provides efficient insertion and deletion operations.Treelist also supports the sub -list of the specified range quickly, and provides the function of sorting in the natural order or custom comparator.The following is the example code of Treelist: List<String> treeList = new TreeList(); treeList.add("Apple"); treeList.add("Banana"); treeList.add("Orange"); System.out.println(treeList); 4. CowalList Cowallist is a thread-safe List implementation. It uses a strategy of copy-on-write when writing, that is, a new copy will be created when modifying the collection, thereby avoiding thread conflicts.The reading operation of Cowallist is no lock, so it has high performance in a multi -threaded environment.The following is the example code of Cowallist: List<String> cowalList = new CopyOnWriteArrayList(); cowalList.add("Apple"); cowalList.add("Banana"); cowalList.add("Orange"); System.out.println(cowalList); In addition to the above List implementation class, Apache Commons Collections also provides many other useful methods and methods that can simplify the operation and processing of the collection.By using the List in Apache Commons Collections, we can process the collection data more flexible and efficiently.These implementation classes provide different characteristics and performance characteristics, and can choose the most suitable implementation class according to specific needs.