Java's first learning and understanding

Let's talk about your knowledge of java. Java is an object-oriented language, while C + + is process-oriented. Java in the development and design of Web pages is essential, in addition we can use it to do mobile mobile development, there are some server-based architecture design. Java introduces the principle of virtual machines and runs on virtual machines to implement different styles of Java interfaces. Java Virtual machine is built on the hardware and operating system, the implementation of Java binary Code interpretation line function function, provided on the interface of different platforms. Java's language style is very close to c,c++, but different from them. Java discards the C + + pointers, operator overloading, multiple inheritance and other characteristics, in order to make the program more concise and easy to maintain, Java encapsulates the data in the class, the encapsulation and inheritance of the class so that the program code only one time, the main thing programmers need to do is to be responsible for the design and application of the class and interface. In Java. The inheritance of a class is single, non-multiplicity, and a subclass has only one parent class, and the parent class of the subclass has a parent class.

The first time we touch Java, we need to understand how to install it. There are two steps: Installing JDK and environment variable configuration. JDK is a great tool installation package: There are a lot of download files and installation packages, JDK compiler, JDK interpreter, Java class library functions, Java operating environment and so on. environment variable Configuration I think it is very difficult to fix the piece, according to the teacher's needs on the desktop right-click on the "My Computer--Properties, advanced environment variable", in the system variables we can see the system's various environment variables value. Double-click a variable to modify the value of a variable, separated by a ";" between the variables, if the environment variable is missing we can also create a new, JDK-related three variables: "Java_home", "path", "Classpath". Set the path of each variable in the JDK, then click "OK" to exit. Then call the command prompt, enter Javac, and if there is a help message showing Java, the environment variable configuration is successful. When the operation must be careful, the environment variable one can not be less, any one of the missing can cause a program failure, unable to run. The most important thing is to add the correct installation path when setting the environment variable value. Once the configuration is successful, we can start running the Java program.

Java's first learning and understanding