Java basic video Notes 1, java basic notes

Java basic video Notes 1, java basic notes
Basic knowledge Software Development

Software: a collection of computer data and commands organized in a specific order.

Common software includes system software and application software

Development: make software.

Human-Computer Interaction

The emergence of software enables better interaction between people and computers.

The interactive mode includes the graphical interface and command line mode.

Common doscommand line commands

Dir: list files and folders in the current directory

Md: create a directory

Rd: delete a directory

Cd: Enter the specified directory

Cd ..: Return to the upper-level directory

Cd/: Return to the root directory

Del: delete an object

Exit: exit the doscommand line.

Enter command line: win + r, Enter cmd, and press enter to enter the interface as follows:

 

The underlying layer of the graphic interface is actually the DOS command.

Computer Language

Communication between people and computers, such as C, C ++, and Java.

Java language Overview

Java is an advanced programming language launched by SUN in 1995. It is an Internet-oriented programming language. With the increasing maturity of Java Technology in the Web field, Java has become the preferred development language for Web applications, it is completely object-oriented and has nothing to do with the platform.

Three technical architectures of Java

J2EE: a solution for developing applications in an enterprise environment.

J2SE: a solution for developing common desktop and business applications.

J2EE: a solution for developing electronic consumption products and embedded devices.

Java features

Cross-platform: applications written in Java can run on different system platforms.

Principle: you only need to install a java Virtual Machine (JVM) on the operating system that runs the Java application. JVM is responsible for running Java programs in this system.

Java environment construction

JRE: Java Runtime Environment, including the core class libraries required by Java virtual machines and Java programs. To run a developed Java program, you only need to install JRE on the computer.

JDK: Java development kit, including java development tools, including JRE. Therefore, if JDK is installed, you do not need to install JRE separately.