1-1-What is Java-Java是什么

What is Java Java是什么

Java is a programming language and a platform. Java is a high level, robust, object-oriented and secure programming language.
Java是一种编程语言，也是一个平台。Java是一种高水平、健壮、面向对象、安全的编程语言。

Java was developed by Sun Microsystems (which is now the subsidiary of Oracle) in the year 1995. James Gosling is known as the father of Java. Before Java, its name was Oak. Since Oak was already a registered company, so James Gosling and his team changed the Oak name to Java.
Java是由Sun Microsystems公司（现在是Oracle的子公司）在1995年开发的。詹姆斯-高斯林被称为Java之父在Java之前，它的名字是Oak。由于Oak已经是一家注册公司，所以James Gosling和他的团队将Oak的名字改成了Java。

Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has a runtime environment (JRE) and API, it is called a platform.
平台(Platform)任何程序运行的硬件或软件环境，都被称为平台。由于Java有运行时环境（JRE）和API，所以称为平台。

Java Example Java示例

Let's have a quick look at Java programming example. A detailed description of Hello Java example is available in next page.
让我们来快速了解一下Java编程实例。Hello Java实例的详细介绍请看下页。

class Simple{  
    public static void main(String args[]){  
     System.out.println("Hello Java");  
    }  
}  

Application 应用

According to Sun, 3 billion devices run Java. There are many devices where Java is currently used. Some of them are as follows:
据Sun公司统计，有30亿台设备运行Java。目前使用Java的设备有很多。其中一些应用如下：

Desktop Applications such as acrobat reader, media player, antivirus, etc.
桌面应用程序，如acrobat阅读器、媒体播放器、杀毒软件等。

Web Applications such as irctc.co.in, javatpoint.com, etc.
Web应用程序，如irctc.co.in、javatpoint.com等。

Enterprise Applications such as banking applications.
企业应用，如银行应用。

Mobile
移动应用

Embedded System
嵌入式系统

Smart Card
智能卡

Robotics
机器人技术

Games, etc.
游戏等。

Types of Java Applications Java应用类型

There are mainly 4 types of applications that can be created using Java programming:
使用Java编程主要有4种类型的应用程序可以创建。

1) Standalone Application 单机应用程序
Standalone applications are also known as desktop applications or window-based applications. These are traditional software that we need to install on every machine. Examples of standalone application are Media player, antivirus, etc. AWT and Swing are used in Java for creating standalone applications.
单机应用也被称为桌面应用或基于窗口的应用。这些都是我们需要在每台机器上安装的传统软件。独立应用程序的例子有媒体播放器、杀毒软件等。在Java中使用AWT和Swing来创建独立应用程序。

2) Web Application Web应用程序
An application that runs on the server side and creates a dynamic page is called a web application. Currently, Servlet, JSP, Struts, Spring, Hibernate, JSF, etc. technologies are used for creating web applications in Java.
在服务器端运行并创建动态页面的应用程序称为Web应用程序。目前，用Java创建Web应用时，主要采用Servlet、JSP、Struts、Spring、Hibernate、JSF等技术。

3) Enterprise Application 企业应用
An application that is distributed in nature, such as banking applications, etc. is called enterprise application. It has advantages of the high-level security, load balancing, and clustering. In Java, EJB is used for creating enterprise applications.
具有分布式性质的应用，如银行应用等，称为企业应用。它具有高级安全、负载均衡、集群等优点。在Java中，EJB用于创建企业应用。

4) Mobile Application 移动应用
An application which is created for mobile devices is called a mobile application. Currently, Android and Java ME are used for creating mobile applications.
为移动设备创建的应用程序称为移动应用程序。目前，Android和Java ME被用于创建移动应用程序。

Java Platforms / Editions Java 平台/版本

There are 4 platforms or editions of Java:
Java有4个平台/版本。

1) Java SE (Java Standard Edition) Java标准版
It is a Java programming platform. It includes Java programming APIs such as java.lang, java.io, java.net, java.util, java.sql, java.math etc. It includes core topics like OOPs, String, Regex, Exception, Inner classes, Multithreading, I/O Stream, Networking, AWT, Swing, Reflection, Collection, etc.
它是一个Java编程平台。它包括java.lang、java.io、java.net、java.util、java.sql、java.math等Java编程API。包括OOPs、String、Regex、Exception、Inner classes、多线程、I/O Stream、Networking、AWT、Swing、Reflection、Collection等核心主题。

2) Java EE (Java Enterprise Edition) Java企业版
It is an enterprise platform which is mainly used to develop web and enterprise applications. It is built on the top of the Java SE platform. It includes topics like Servlet, JSP, Web Services, EJB, JPA, etc.
它是一个企业平台，主要用于开发Web和企业应用。它是建立在Java SE平台之上的。它包括Servlet、JSP、Web服务、EJB、JPA等主题。

3) Java ME (Java Micro Edition) Java迷你版
It is a micro platform which is mainly used to develop mobile applications.
它是一个微平台，主要用于开发移动应用。

4) JavaFX
It is used to develop rich internet applications. It uses a light-weight user interface API.
它用于开发丰富的互联网应用。它使用一个轻量级的用户界面API。

Prerequisite 学习要求

To learn Java, you must have the basic knowledge of C/C++ programming language.

要跟随本教程，必须具备C/C++编程语言的基本知识。

Audience 适合人群

Our Java programming tutorial is designed to help beginners and professionals.

我们的Java编程教程旨在帮助初学者和专业人士。

Problem 问题

We assure that you will not find any problem in this Java tutorial.
我们保证您在本Java教程中不会发现任何问题。

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