Article Directory
Software development introduction
Divided into system software and application software .
Human-computer interaction:
- Graphical interface
Graphical User Interface, GUI - Command Line Interface
Command Line Interface, CLI
Commonly used DOS commands
dir, md, rd, cd, cd …, cd, del, exit, echo, etc.
Programming language introduction
Machine language (binary code) —> Assembly language (mnemonic) —> High-level language
High-level language: process-oriented, object-oriented
Why Java?
The use of Java in the Android system
Java language overview
A high-level programming language launched by SUN (Stanford University Network) in 1995, a pure object-oriented language.
Application areas:
- Enterprise-level applications: enterprise software systems, various websites
- Android platform application
- Big data platform development
Father of Java: James Gosling
Java language operating mechanism and operating process
Object-oriented (encapsulation, inheritance, polymorphism), robustness, and cross-platform (JVM).
Java has two core mechanisms: garbage collection mechanism, JVM.
Java language environment construction
JDK: Java Development Kit, Java Development Kit
JRE: Java Runtime Environment, Java Runtime Environment
JVM: Java Virtual Machine, Java Virtual Machine
JDK = JRE + development tool set
JRE = JVM + Java SE standard class library
Development experience-HelloWorld
.java (source program)
is compiled by javac command to get .class (bytecode file) and the result is
obtained by running the .class file by java command.
Comment
- Single line comment
// 单行注释
- Multi-line comments
/*
多行注释
*/
- Document comments: can be parsed by javadoc tool to generate documents in the form of web files.
/**
@ auther alibli
@ version v1.0
文档注释
*/
Java API documentation
API: Application Programming Interface, application programming interface, commonly known as class library.