12 Questions Usually Asked at J2EE Interviews (With Example Answers)
If you want to get a job as a Java developer, you may need to show that you know J2EE during an interview. To prepare for your interview, you can make a great impression by going over common J2EE interview questions and practicing how you would answer them. Usually Asked at J2EE Interviews
In this article, we’ll look at some common J2EE interview questions and give examples of how to answer them.
Sample answers to the most common J2EE interview questions
Employers usually ask you questions at an interview to see how well you know the basics of the J2EE platform. Some questions are asked to see how well you know how certain parts and functions of J2EE work. Most of the time, interviewers want clear, technical answers to these questions. Some questions will ask you to list the pros and cons of using J2EE, while others will ask you to compare what you know about J2EE to what you know about other platforms.
Here are 12 questions about J2EE that are often asked during interviews:
What is the J2EE?
People often ask this question to see how well you understand the platform. You can say what it means in your own words and talk about some of the ways it can be used. For a good answer, you might talk about how you’ve used J2EE before.
“J2EE” is short for “Java 2 Platform Enterprise Edition.” With a set of protocols and application programming interfaces, the J2EE platform is used to make multi-tiered web applications (APIs). J2EE is a faster, safer, and more secure Java platform for the enterprise level. It is an improvement over J2SE (Java 2 Platform, Standard Edition). The J2EE platform makes it easier and cheaper to build, deploy, and change applications with multiple layers.
J2EE applications are made up of what parts?
This question is your chance to show your familiarity with the foundations of J2EE, which can show that you understand the platform and its uses.
Example: “There are four main components, or tiers, of J2EE applications. The presentation component is the layer of the client-tier that the client can see. It runs on the server of the client. The J2EE server is what runs the application layer, which is the web-tier layer. Servlet and JSP technologies are used as parts of the application. The J2EE server runs the business component, which is the business layer. JavaBeans are part of the business component. The last part is the resource adaptor.”
What are some common clients of J2EE?
Use this question to show how much you know about how to use J2EE. You could list a few clients and explain how each one uses J2EE. This can help you give a more detailed answer, but a short list might also do.
“Applets, application clients, Java Web Start-enabled clients, and wireless clients are all types of J2EE clients.”
What is a container for J2EE?
You might be asked to explain other important J2EE terms. This question is meant to see if you can use common language in a clear and confident way, as it is often used in places of work that deal with J2EE. For a good answer, explain what it means and how it can be used.
Example: “A server platform that runs a J2EE application is called a container. With APIs from the Web container and the EJB container, a Java component can run on the J2EE container.
To explain more about what each sub-container does, the web container is a server platform used to run JSPs and servlets. The EJB container is a server platform used to control how Enterprise Beans are run.
Explain what Hibernate is and give some examples of what it can’t do and what it can do well.
People who work with J2EE and other services often use this service. Think about explaining what Hibernate is and how it is used in J2EE in your own words. For the second part of the question to work best, you should explain why some things are helpful or not.
Example: “Hibernate is an object-relational mapping and query service that you can use for free. Hibernate lets us use a SQL extension to write HQL (hibernate query language) scripts, which is much faster than writing scripts in native SQL (structured query language).
There are many good reasons to use hibernate. It works with any database, and its standard ORM also works with JPA (Java Persistence API). It also has mapping between domain objects and the regional database. Plus, the connection to the database is better with Hibernate than with JDBC.
There are some bad things about using hibernate as well. It takes longer to run queries because HQL is used. It only works with HQL for composite keys, which limits the options for more advanced queries. Also, it doesn’t have any references to shared values.”
What is an ORM, and how does it work in J2EE?
Professionals who work with J2EE and other Java platforms often use a method called “object-relational mapping.” For a good answer, you should define the term and talk about how you’ve used it before. This strategy can help you show that you have worked on similar projects before.
“ORM stands for “object-relational mapping.” It is the object in a Java class that is mapped into the tables of a relational database using the metadata that describes the object mapping and the database. This process changes the way the data is shown from one way to another.”
What are some good things about ORM?
People often ask this question in relation to what it means and what it can be used for. You can use this question to tell us more about your ORM experience by telling us how it has helped your work.
Example: “ORM has a number of important benefits. The first is increased productivity, since ORM makes code automatically based on the data model. This saves time when writing code to access data. The ability to be fixed is another. The codes that are made for ORM are tested carefully. As long as the developer builds in the right features, there isn’t much maintenance to do.
Another benefit is how well it works. The code that the ORM makes takes care of all the data access needs of the application. The code that is made is also optimized to make it faster to get to the data. The last is vendor independence. ORM doesn’t depend on any one vendor for the code that it makes. This will make the app easier to move around.”
Explain the goals of the design of the J2EE architecture.
This question is meant to see if you know what the goals of the platform are. You can make your answer even better by talking about how these goals have affected the work you’ve done in the past.
Example: “Some of the main goals of designing the J2EE architecture are to make it available and easy to use. The platform is made to always be connected and ready to be used. Users should be able to connect to the app and use it from any device, including desktop computers, laptops, and cell phones.
What are a J2EE architect’s responsibilities?
If you are interviewing for a job as an architect, you are likely to be asked this question to see how well you understand the job. Explain in your own words what this role is for and how important it is. If you want to show how good you are at being a J2EE architect, you could use examples from your professional life.
Example answer: “The architect is in charge of imagining how the system will work and making a plan for it. The architect is also in charge of figuring out how the system’s parts work together and figuring out how the functional and non-functional requirements fit together.
What is a hashtable, and how does J2EE use it?
If you work with J2EE, you may need to know how to use a lot of different tools. Use this question to explain what the tool, a hashtable in this case, is and how you have used it in the past.
Example: “A hashtable is a data structure that links keys to values and makes it easy to add and find data quickly. A key or value can be any object that is not null. To use a hashtable in J2EE, you must specify the object that will be used as the key and the value that you want to be linked to that key. After the object and value of the key are set, the key is hashed. The hash code that comes out shows where in the table the value is stored.
What is a J2EE module, and what are the four modules that are used?
This is another question to see how well you know terms and how things work. You can use it to explain what the term means and what each part is. You could also talk about how you might use or have used each module.
Example: “A module in J2EE is one or more components of the same container type and one component deployment descriptor of the same type.” J2EE is made up of four different modules:
- The Application Client Module, which comes in a file with the extension.jar and is called a JAR file. It contains class files and a client deployment descriptor.
- The WEB Module comes as a JAR file with the extension.wav. It has JSP (Java server page) files, GIF files, and HTML files. It also has class files for servlets, a web deployment descriptor, and a web deployment descriptor.
- The Enterprise JavaBeans (EJB) Module, which comes in a file with the extension.jar and is called a JAR file. It has an EJB deployment descriptor and class files for enterprise beans.
- The Resource Adapter Module comes as a JAR file with the extension.rar. It contains classes, a resource adapter deployment descriptor, Java interfaces and native libraries.”
12. What’s the difference between.ear,.jar, and.war files?
In jobs that use J2EE or other Java platforms, it is often important to understand how things are put together and how they work. You might be asked to explain the platform’s different operational and organizational functions. Use this question to explain how each type of file is different. You could also give examples of how you’ve interacted with each type to show that you’re familiar with them.
Example answer: “Each of these files is made up of different parts that are handled differently by J2EE components like servlet containers, EJB containers, and applications servers.”
- The parts of.ear files are Web, EJB, and client.
- There are class files, library files, resource files, and other files in.jar files.