国外的一些J2EE面试题一


Posted in 面试题 onOctober 13, 2012
Question: What is J2EE?
Answer: J2EE Stands for Java 2 Enterprise Edition. J2EE is an environment for developing and deploying enterprise applications. J2EE specification is defined by Sun Microsystems Inc. The J2EE platform is one of the best platform for the development and deployment of enterprise applications. The J2EE platform is consists of a set of services, application programming interfaces (APIs), and protocols, which provides the functionality necessary for developing multi-tiered, web-based applications. You can download the J2EE SDK and development tools from http://java.sun.com/.

Question: What do you understand by a J2EE module?
Answer: A J2EE module is a software unit that consists of one or more J2EE components of the same container type along with one deployment descriptor of that type. J2EE specification defines four types of modules:
a) EJB
b) Web
c) application client and
d) resource adapter

In the J2EE applications modules can be deployed as stand-alone units. Modules can also be assembled into J2EE applications.

Question: Tell me something about J2EE component?
Answer: J2EE component is a self-contained functional software unit supported by a container and configurable at deployment time. The J2EE specification defines the following J2EE components:

* Application clients and applets are components that run on the client.
* Java servlet and JavaServer Pages (JSP) technology components are Web components that run on the server.
* Enterprise JavaBeans (EJB) components (enterprise beans) are business components that run on the server. J2EE components are written in the Java programming language and are compiled in the same way as any program in the language. The difference between J2EE components and “standard” Java classes is that J2EE components are assembled into a J2EE application, verified to be well formed and in compliance with the J2EE specification, and deployed to production, where they are run and managed by the J2EE server or client container.

Source: J2EE v1.4 Glossary

Question: What are the contents of web module?
Answer: A web module may contain:
a) JSP files
b) Java classes
c) gif and html files and
d) web component deployment descriptors

Question: Differentiate between .ear, .jar and .war files.
Answer: These files are simply zipped file using java jar tool. These files are created for different purposes. Here is the description of these files:
.jar files: These files are with the .jar extenstion. The .jar files contains the libraries, resources and accessories files like property files.
.war files: These files are with the .war extension. The war file contains the web application that can be deployed on the any servlet/jsp container. The .war file contains jsp, html, javascript and other files for necessary for the development of web applications.
.ear files: The .ear file contains the EJB modules of the application.

Question: What is the difference between Session Bean and Entity Bean?
Answer:
Session Bean: Session is one of the EJBs and it represents a single client inside the Application Server. Stateless session is easy to develop and its efficient. As compare to entity beans session beans require few server resources.

A session bean is similar to an interactive session and is not shared; it can have only one client, in the same way that an interactive session can have only one user. A session bean is not persistent and it is destroyed once the session terminates.

Entity Bean: An entity bean represents persistent global data from the database. Entity beans data are stored into database.

Question: Why J2EE is suitable for the development distributed multi-tiered enterprise applications?
Answer: The J2EE platform consists of multi-tiered distributed application model. J2EE applications allows the developers to design and implement the business logic into components according to business requirement. J2EE architecture allows the development of multi-tired applications and the developed applications can be installed on different machines depending on the tier in the multi-tiered J2EE environment . The J2EE application parts are:

a) Client-tier components run on the client machine.
b) Web-tier components run on the J2EE server.
c) Business-tier components run on the J2EE server and the
d) Enterprise information system (EIS)-tier software runs on the EIS servers

Question: Why do understand by a container?
Answer: Normally, thin-client multi-tiered applications are hard to write because they involve many lines of intricate code to handle transaction and state management, multithreading, resource pooling, and other complex low-level details. The component-based and platform-independent J2EE architecture makes J2EE applications easy to write because business logic is organized into reusable components. In addition, the J2EE server provides underlying services in the form of a container for every component type. Because you do not have to develop these services yourself, you are free to concentrate on solving the business problem at hand (Source: http://java.sun.com/j2ee/1.3/docs/tutorial/doc/Overview4.html ).

In short containers are the interface between a component and the low-level platform specific functionality that supports the component. The application like Web, enterprise bean, or application client component must be assembled and deployed on the J2EE container before executing.

Question: What are the services provided by a container?
Answer: The services provided by container are as follows:
a) Transaction management for the bean
b) Security for the bean
c) Persistence of the bean
d) Remote access to the bean
e) Lifecycle management of the bean
f) Database-connection pooling
g) Instance pooling for the bean

Question: What are types of J2EE clients?
Answer: J2EE clients are the software that access the services components installed on the J2EE container. Following are the J2EE clients:
a) Applets
b) Java-Web Start clients
c) Wireless clients
d) Web applications

Tags in this post...

面试题 相关文章推荐
error和exception有什么区别
Oct 02 面试题
JAVA和C++区别都有哪些
Mar 30 面试题
北京SQL新华信咨询
Sep 30 面试题
面向对象概念面试题(.NET)
Nov 04 面试题
接口可以包含哪些成员
Sep 30 面试题
C# Debug和Testing相关面试题
Oct 25 面试题
用Python匹配HTML tag的时候,<.*>和<.*?>有什么区别
Nov 04 面试题
如何防止同一个帐户被多人同时登录
Aug 01 面试题
介绍下Java中==和equals的区别
Sep 01 面试题
创立科技Java面试题
Nov 29 面试题
初级Java程序员面试题
Mar 03 面试题
Delphi工程师笔试题
Sep 21 面试题
J2EE模式面试题
Oct 11 #面试题
J2ee常用的设计模式?说明工厂模式
May 21 #面试题
J2EE相关知识面试题
Aug 26 #面试题
J2EE中常用的名词进行解释
Nov 09 #面试题
创联软件面试题笔试题
Oct 07 #面试题
解释下面关于J2EE的名词
Nov 15 #面试题
一个J2EE项目团队的主要人员组成是什么
Jun 04 #面试题
You might like
PHP XML error parsing SOAP payload on line 1
2010/06/17 PHP
php排序算法(冒泡排序,快速排序)
2012/10/09 PHP
ThinkPHP中ajax使用实例教程
2014/08/22 PHP
实现PHP+Mysql无限分类的方法汇总
2015/03/02 PHP
Laravel 5框架学习之环境与配置
2015/04/08 PHP
javascript 面向对象全新理练之继承与多态
2009/12/03 Javascript
javascript smipleChart 简单图标类
2011/01/12 Javascript
通过Javascript创建一个选择文件的对话框代码
2012/06/16 Javascript
浅析JavaScript中的常用算法与函数
2013/11/21 Javascript
Document.location.href和.replace的区别示例介绍
2014/03/04 Javascript
node.js中的buffer.length方法使用说明
2014/12/14 Javascript
jQuery实现带滑动条的菜单效果代码
2015/08/26 Javascript
js弹出框、对话框、提示框、弹窗实现方法总结(推荐)
2016/05/31 Javascript
js定义类的几种方法(推荐)
2016/06/08 Javascript
require.js 加载 vue组件 r.js 合并压缩的实例
2016/10/14 Javascript
vue.js指令v-model使用方法
2017/03/20 Javascript
AngularJs中$cookies简单用法分析
2019/05/30 Javascript
Vue 中使用 typescript的方法详解
2020/02/17 Javascript
Jquery cookie插件实现原理代码解析
2020/08/04 jQuery
Vue+Bootstrap实现简易学生管理系统
2021/02/09 Vue.js
Python实现Pig Latin小游戏实例代码
2018/02/02 Python
Python实现上下班抢个顺风单脚本
2018/02/07 Python
Python制作exe文件简单流程
2019/01/24 Python
python 协程中的迭代器,生成器原理及应用实例详解
2019/10/28 Python
Python判断远程服务器上Excel文件是否被人打开的方法
2020/07/13 Python
Python命令行参数定义及需要注意的地方
2020/11/30 Python
HTML5 Canvas绘制圆点虚线实例
2015/01/01 HTML / CSS
Kipling凯浦林美国官网:世界著名时尚休闲包袋品牌
2016/08/24 全球购物
WoolOvers爱尔兰:羊绒、羊毛和棉针织品
2017/01/04 全球购物
美国NBA官方商店:NBA Store
2019/04/12 全球购物
Notino希腊:购买香水和美容产品
2019/07/25 全球购物
幼儿园家长会邀请函
2014/01/15 职场文书
公司爱心捐款倡议书
2014/05/14 职场文书
公司合作协议范文
2014/10/01 职场文书
Golang Gob编码(gob包的使用详解)
2021/05/07 Golang
CentOS7环境下MySQL8常用命令小结
2022/06/10 Servers