Class and interfaces commonly used in the core framework in the Java class library

The core framework in the Java class library is an important part of the Java programming language. It contains many commonly used classes and interfaces that can help developers write high -efficiency and reliable Java applications.These classes and interfaces provide rich functions and characteristics, which can simplify the development process and improve the reinnerstability of the code. 1. Object class: Object is the root class of all Java categories.Flexible and easy to maintain. 2. String class: String class is a class used in Java to represent string. It provides rich string operation methods, such as substring (), indexof (), touppercase (), etc., which can be easily processed to the stringOperation. 3. List interface: List is a collection interface in Java, which indicates a orderly collection that can contain repetitive elements.The commonly used implementation classes include ArrayList and LinkedList. They provide rich methods, such as ADD (), Remove (), GET (), etc., which can easily operate the set. 4. MAP interface: Map is a mapping interface in Java. It indicates a set of a set of key -value pairs. The commonly used implementation classes include HashMap and TreeMap. They provide rich methods, such as Put (), Get (), Remove () Wait, you can easily operate the key values. 5. Thread class: Thread class is a class that represents a thread in Java. It provides rich methods and attributes that can easily control the creation, start, suspension and termination of threads to achieve multi -threaded programming. In addition to the class and interfaces listed above, the core framework in the Java class library also contains many other commonly used classes and interfaces, such as IO, network category, date and time category.Meet different development needs. In actual programming, developers can quickly build and develop Java applications by introducing the core frameworks in the Java class library to improve development efficiency and code quality.At the same time, it can also expand and customize its own functions by inheriting and implementing these classes and interfaces to achieve more flexible and maintainable code. The following is a simple Java program example. It demonstrates how to use the list interface and ArrayList class in the core framework in the Java class library: import java.util.List; import java.util.ArrayList; public class Main { public static void main(String[] args) { List<String> list = new ArrayList<>(); list.add("Hello"); list.add("World"); for (String str : list) { System.out.println(str); } } } In this example, we first introduced the List and ArrayList class, and then created an ArrayList object, adding two string to it, and finally traversing and printing the elements in the list through FOR.Through this example, you can see the simple and powerful functions of the core framework in the Java library, which can help developers to quickly achieve various functions.