Learning the Java Language (2) : Classes and Objects

Classes and Objects

Learning the Java Language (1) : Language Basics

Variable 變量 變數

Lesson: Object-Oriented Programming Concepts

Lesson: Object-Oriented Programming Concepts
(物件導向元件)

Object(物件), Class(類別), Inheritance(繼承), Interface(介面), Package(封包)

Object
1. 狀態與行為
    任何東西都有"狀態與行為"，例如狗狗有狀態[名字、顏色、血統、飢餓度]；有行為[吠、撿東西、搖尾巴]

First hello world

from "http://docs.oracle.com/javase/tutorial/index.html"

class HelloWorldApp {
    public static void main(String[] args) {
        System.out.println("Hello World!"); // Display the string.
    }
}

1. class named HelloWorldApp

2. public static void main(String[] args)

   "public static" 可以交換順序，一般寫為public static

   args 為 arguments (?)，一般寫為args或argv

   基本的main

3. String[] args (不確定,這邊說ignore augrments)

4. System.out.println 輸出文字指令