Introduction to Java

Java Overview

1991 Sun's James Gosling and others began developing a language named Oak that would be used to control a microprocessor embedded in a cable switch box PDA.

1994 renamed the Oak language to Java

Three technical architectures for Java

Java EE: Platform Enterprise Edition application for Web program Development

Javase: Java Platform Standard Edition The completion of desktop application development is the basis of the other two

Javame: Java Platform Micro Edition development of electronic consumer products and embedded devices such as mobile programs

Jdk

Java Development Kit Java Development and runtime Environment Java Development tools and JRE

Jre

Java Runtime Environment Java Program run environment Java Runtime required class library +JVM (Java virtual machine)

Configuring Environment variables

Let the tools in the Java Jdk\bin directory run in any directory because the directory where the tool is located tells the system that the system helps us find the specified directory when using the tool

Permanent configuration mode: java_home=% installation path%\JAVA\JDK Path=%java_home%\bin

Temporary configuration mode: Set path=%path%; C:\Program Files\java\jdk\bin Features: The system defaults to the current path to find the program to execute if you do not go to the path set in the paths to find

Javac Commands and Java commands

Javac: The compiler that is responsible for compiling the part when executing javac will start the Java compiler program to compile a. java file with the specified extension to generate a bytecode file that the JVM can recognize. The class file is Java's running program

Java: The part responsible for running starts the JVM loading the class library required by the runtime and executes a file for the class file to be executed must have a starting point for execution The starting point is the main function

Introduction to Java