0-java Overview

table of Contents

Java development history

java specification

Java three branches

Java SE Learning Path

HelloWorld

1, Java development history

- Java company was born in sun

- sun was acquired by Oracle Corporation

2, java specification

- Java Java specification defines the syntax and functionality

- jcp in charge of Java Specification

- jdk implements the Java specifications

- jdk there are several versions

sun jdk highest market share (over 90%)

open jdk

IBM jdk fastest

- jdk1998 / jdk1.2-1.4 collectively referred to as Java2

- 2014 / jdk8.0 (long version) /2019.1 stop updating

- 2018.9 / jdk11 (long version)

3, Java three branches

- Java SE (standard Edition) PC-oriented application development is the foundation

- Java EE (Enterprise Edition) for Enterprise Application Development

Java ME (micro Edition) for embedded application development

4, Java Learning Path

- Basic sentence structure and

- Object-oriented thinking (focus)

- Integrated and polymorphism (focus)

- Exception Handling

- data structure

- File Handling

5、HelloWorld

public class HelloWorld{

    public static void main(String[] args){

        System.out.println("Hello World")

    }

}