Java language is a high-level programming language launched by SUN (Stanford University Network) in 1995. It was initially mainly used in small consumer electronic products. Later, with the rise of the Internet, Java language rose rapidly (Java applets can Run in the browser), becoming the preferred language for large Internet projects.
On April 20, 2009, Oracle acquired Sun for US$7.4 billion and obtained the copyright of Java.
Java is an object-oriented language. Readers who do not have the experience of object-oriented programming need to spend a lot of time understanding object-oriented concepts, grammar and programming ideas. If you don’t understand it, please insist on it. If you spend more time writing code, you will naturally be enlightened. Be cheerful, from process-oriented to facial objects, requires an adaptation period.
Java is not just a programming language, it is a complete platform with huge libraries that maximizes the simplification of complex operations such as graphics drawing, Socket connection, database access, etc.
Java is cross-platform, compiled at once and runs everywhere. The code written on Windows can be ported to Linux without modification, and vice versa.
In the world programming language rankings, Java almost occupies the second place, second only to C.
Java is a typical object-oriented language, released later than C++. Some syntax and ideas also refer to C++. Please see the following table:
Although people find that the syntax of C++ is too complicated and has a lot of redundancy, Java is still as close to C++ as possible when designing it, reducing people's learning costs. Java syntax is a "pure" version of C++ syntax, without header files, pointer arithmetics (or pointer syntax), structure, union, operator overloading, virtual base classes, etc. Readers with a C++ foundation can easily switch to Java.
Java is widely used:
1.Web development: Java is very suitable for developing large-scale corporate websites, such as the background of Renren and Qunar.com are all Java.
2. Android development: Almost all APPs on Android mobile phones are developed in Java, such as QQ, WeChat, and UC browsers.
3. Client development: Java can also be used to develop software on computers, such as Elicpse and Netbeans.
4. Embedded applications: Embedded applications are software that runs in small electronic products, such as software on old mobile phones and software on MP3.
However, I can tell you responsibly that Java's current main application directions are web development and Android development, and most Java programmers recruited by IT companies are also engaged in these two aspects.
Java's GUI library is not outstanding, and many users are not used to its interface; Java's client resources consume a lot; more importantly, Java programs must be run with the help of virtual machines, and the operating system does not have a virtual machine installed by default ( The next section will introduce in detail). There are very few client programs for ordinary users that are directly launched on the market, developed in Java.
In terms of embedded, Java is difficult to operate the underlying hardware, has little flexibility, and requires virtual machine support, which occupies a lot of resources, which is a bit difficult for microcontroller systems with very low configurations. Therefore, in applications that strive to be efficient, miniaturized, and perform critical missions, assembly and C languages are best used, such as rocket control, sensor communication or reporting the orientation of the spacecraft.
Although Java is a language with complete functions, it has its own aspects of being good at and not being good at. Everyone should learn to make choices in specific projects.