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1、2022最新国外J2EE工程师面试题最新国外J2EE工程师面试题集锦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 develo
2、pment 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
3、 tools from 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) EJBb) Webc) applicatio
4、n client andd) resource adapterIn 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
5、 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
6、) 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
7、 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 GlossaryQuestion: What are the contents of web module?Answer: A web module
8、 may contain:a) JSP filesb) Java classesc) gif and html files andd) web component deployment descriptorsQuestion: 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
9、 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 cont
10、ainer. 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
11、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,
12、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 suita
13、ble 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 archit
14、ecture 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 o
15、n the J2EE server.c) Business-tier components run on the J2EE server and thed) Enterprise information system (EIS)-tier software runs on the EIS serversQuestion: Why do understand by a container?Answer: Normally, thin-client multi-tiered applications are hard to write because they involve many lines
16、 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
17、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: ).In short containers are the interface between a compo
18、nent 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 ser
19、vices provided by container are as follows:a) Transaction management for the beanb) Security for the beanc) Persistence of the beand) Remote access to the beane) Lifecycle management of the beanf) Database-connection poolingg) Instance pooling for the beanQuestion: What are types of J2EE clients?Ans
20、wer: J2EE clients are the software that access the services components installed on the J2EE container. Following are the J2EE clients:a) Appletsb) Java-Web Start clientsc) Wireless clientsd) Web applications本文来源：网络收集与整理，如有侵权，请联系作者删除，谢谢！第9页 共9页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页第 9 页 共 9 页