Java and network

Since its birth, Java has been inseparable from the network. The feature of Java is that it can make the most of the network. Java applications in the network are roughly divided into two types: Web browsing and network application systems.
 
1. Web browsing

Web browsing is currently the main method of using the Internet. Users can use a browser to access HTML documents on the network to obtain text, images, and various multimedia information. Java programs that can run on Web pages are called "small applications" or "program slices". They are actually bytecode rather than Java source files, therefore, you can directly download the package from the Internet and run it on a local web browser. To be able to use a small application normally, your web browser must be Java compatible and used to explain bytecode. However, early browsers may support different Java standards of different versions due to different manufacturers, so it is difficult to use the latest Java features in small applications. To improve this situation, Sun has implemented the "Java Plug-in", which allows the latest Java Runtime Environment to be applied to mainstream browser products at the same time.
Applet is a small application program written in Java and runs in the browser of the client. It extends the functions of the browser; servlet is a small application program written in Java and runs in the Server Browser. It extends the functions of the Web server. Similar to the use of Applet and Servlet, Web browsing has made great progress in terms of security, dynamic nature, and platform independence. However, when using Servlet, the generation of webpage content must be completed by writing code, and all updates must be performed by developers during the update process, resulting in a heavy workload. In this case, JSP is born. It can embed Java code into HTML files, and the server will automatically create a Servlet File for the page. JSP is considered a simple servlet method. Since then, the application of Applet, Servlet, and JSP Technology in Web browsing further enhances the Web service capabilities.

2. network application system
Because Java is platform independent, network application systems developed using Java can run on various platforms, greatly enhancing the code reuse rate and improving system development efficiency, this reduces the repetitive work of programmers. Moreover, the network functions inherited by Java are conducive to the development of network applications.

3. Java program classification

Depending on the implementation environment, Java programs can be roughly divided into the following 5 types.

(1) Java application: An Independent Java application.

(2) Java Applet: A small Java application, usually running in a user's browser.

(3) Java servle: the Java Server applet is essentially a Java class that runs on the Web server, receives client requests, and automatically generates dynamic web pages to return to the client.

(4) JSP (Java Server Page): A technology used to generate dynamic web pages, similar to ASP. Based on the servplet technology, it can implement separation of program and page format control. JSP can quickly develop web-based, platform-independent applications. The JSP program also runs on the Web server.

(5) JavaBeans: Reusable Java program components independent from the platform. Using corresponding development tools, you can directly embed them into other Java applications.