Java is a programming language introduced by Sun Company. It is a language executed by interpretation, and its grammatical rules are similar to those of C++. Meanwhile, Java is a cross-platform programming language. A program written in the Java language is called an Applet. It is compiled into a class file by the compiler, stored in the WWW page, and marked on the HTML file accordingly. As long as the client installs Java client software, it can run "applets" directly on the Internet. Java is very suitable for enterprise network and Internet environment, and now it has become one of the most popular and influential programming languages on the Internet. Java has many commendable advantages, such as simplicity, object-oriented, distributed, explanatory, reliability, security, structural neutrality, portability, high performance, multithreading, dynamic and so on. Java abandons all kinds of functions that do more harm than good in C++ and many functions that are rarely used. Jave can run on any microprocessor, and programs developed in Java can be transmitted on the network and can run on any client.

Java is widely used. At present, the most promising development language is Java, which is cross-platform. Write once, run everywhere is a slogan of Java. To learn application programming, you can write programs on the computer, learn applets, embed applets in web pages, learn J2ME, and run programs on mobile phones. Java is everywhere.

Java environment can be used to develop application software that can run on any computing platform. It is actually a very basic and compact technology, and its overall impact on the World Wide Web and commerce can be compared with the impact of spreadsheets on personal computers.

Java is far more than a programming language. It is a complete internal and external computing environment, with everything from development tools, operating systems, server software and thin/thick clients to network management tools, support, training, consulting and integration services.