Introduction to the "dynamic set 'framework in the Java class library

Introduction to the "dynamic set 'framework in the Java class library In Java programming, dynamic collection is an abstract data structure for storing and operating data.The Java class library provides some powerful dynamic set frameworks to solve various data management problems.These frameworks provide a series of interfaces and classes that enable us to operate and manage data easier. The most commonly used dynamic set framework in the Java class library is the collection interface and specific implementation class.The collection interface mainly includes List, SET and MAP.List is an orderly dynamic set that can contain duplicate elements.SET is an disorderly dynamic collection and does not allow duplicate elements.MAP is a collection of key-value pair, which allows us to access the corresponding value through the key. The following is an example code that demonstrates how to use the dynamic set framework in the Java class library: import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class DynamicCollectionExample { public static void main(String[] args) { // Create an ArrayList List<String> names = new ArrayList<>(); // Add element to the list names.add ("Zhang San"); names.add ("Li Si"); names.add ("Wang Wu"); // Traversing the list and printing elements for (String name : names) { System.out.println(name); } // Create a hashmap Map<String, Integer> grades = new HashMap<>(); // Add key value and go to MAP grades.put ("Zhang San", 90); grades.put ("Li Si", 85); grades.put ("Wang Wu", 95); // Traversing MAP and printing key values pair for (Map.Entry<String, Integer> entry : grades.entrySet()) { System.out.println (entry.getkey () + "is" + entry.getValue ()); } } } The above code demonstrates how to use the two specific dynamic sets of ArrayList and HashMap.We can use the ADD () method to add elements to ArrayList, and use the get () method to obtain the element of the specified position.Similarly, in the HashMap, use the put () method to add key value pairs, and use the get () method to obtain the corresponding value according to the key. In addition to these basic dynamic sets, the Java class library also provides some other collection interfaces and implementation classes, such as Queue, Deque, and SortedSet.Each collection has different characteristics and applicable scenarios. Developers can choose the appropriate collection framework according to specific needs. In short, the dynamic set framework in the Java class library provides us with rich data management tools, so that we can more conveniently operate and manage data.Understanding and familiar with the use of these collection frameworks will be very helpful for Java developers.