Frequently Asked J2EE Interview Questions and Answers You Must Read

Introduction

We have curated top Java J2EE interview questions to help you ace your upcoming interview. It's crucial for developers to have knowledge and proficiency in J2EE concepts because it's still the most commonly utilized standard among Java developers. You can also check out our top core java interview questions and answers to brush up your core concepts first.

In this blog, we've compiled a list of 40 most frequently asked J2EE interview questions for both experienced professionals and freshers. So let's begin the drill.

J2EE Interview Questions & Answers For Freshers

So let’s get started with the first set of J2EE interview questions which is primarily useful for freshers.

Q1). Name the major components for J2EE apps briefly?

The major components of any J2EE web-enabled app include – client-tier components, business tier components, web tier components, and EIS (Enterprise Information System) components etc.

• Client-tier components are made to run on client machines.
• Web tier components are made to run on J2EE server.
• Business tier components are made to run on J2EE server, and
• EIS components run over the EIS server.

Q2). Name the different types of J2EE clients?

Q3). Define the struts in the J2EE framework?

This is one of the toughest Java J2EE questions and that's why many candidates don't pay attention to it.

Structs are based on MVC (Model-View-Controller) architecture used to design applications for large enterprises. It can be described in detail as follows –

Model – The internal state of a system is defined by Model. It may be either single or a cluster of Java Beans based on app architecture.

View – The view of any enterprise app is usually designed by JSP technology.

Controller – It is used to process the client request and respond accordingly based on the request. Basically, it is used to manage the actions of users.

Q4). How do you create an interactive user interface for J2EE applications?

You must choose JSF if you want to create interactive User Interfaces in J2EE (Java Server Faces). Based on MVC architecture and design principles, the framework includes a larger collection of reusable user interface components. Additionally, the JSF manages the automatic data that is generated at the server and displayed at the client.

Q5). 3. Which technologies are offered by the J2EE platform?

J2EE offers a number of significant technologies, including:

The Java API for XML-Based Remote Procedure Calls (JAX-RPC) is used to create web services and clients that use XML with RPC.

XML and HTML texts are delivered via Java Server Pages (JSP). In addition to these, we may provide other sorts of data using OutputStream.

Java Servlets: The request-response model can be used to access Servlets, which are classes used to expand the server's functionality and host applications.

Q6). Define Hibernate and HQL?

Hibernate is an open-source query and object-relational mapping service. Here, you can write HQL (Hibernate Query Language) scripts instead of using SQL that saves a lot of time and effort. Hibernate is closely related to composition, polymorphism, inheritance, and collections. With the help of this framework, you can process queries beautifully by using simple Java objects.

Be confident when you answer the J2EE interview question and answer. Take your time to recollect and be brief. 

Q7). Explain the limitation of Hibernate, if any?

The execution of queries is slower.

There is only HQL support for composite keys.

There are no shared references to the value type.

Q8). Explain the major benefits of Hibernate?

Hibernate is independent of database and vendor so it is termed as the portable framework.

Domain objects can be mapped to relational databases.

JPA support for standard ORM.

The database connectivity is better in Hibernate when compared to JDBC.

Q9). What are web components and how useful are they?

The web components that dynamically receive user requests and respond appropriately are Java Servlets or Java Server Pages. To create more static content for the web pages, JSP pages are further run as servlets. This is one of the most important J2EE interview questions.

Q10). What is ORM and how does J2EE use it?

In J2EE, ORM is referred to as object-relational mapping. By converting data from one form to another, the objects are translated into tables in the relational databases.

J2EE Interview Questions & Answers For Experienced

Let's move on to our final set of Advanced J2EE Interview Questions, which are primarily helpful for working professionals with expertise.

Q11). How will you define save () or update () methods in Hibernate?

Save () Update ()

It is used to save or store an object in the database. It creates a new entry every time you create a fresh object. It is used to update the existing objects once the record is found with the help of an identifier.

Q12). How will you differentiate the get () and Load () methods?

Load () Get ()

If an object is not found either in Cache or database, Load () method will throw an exception. If an object is not found in Cache or database, then the Get () method returns a null value, not the exception.

Q13). List the advantages of ORM (object-relational mapping)?

Productivity – The automatic code is generated that minimizes the overall data access time based on the data model defined.

Performance – The complete data access needs of an application are managed by the automated code generated by the ORM. Because there is no need for any extra code so the overall data access process is made faster and optimized.

Vendor independent – The code generated is independent of the vendor that increased the overall portability of an application.

Maintainability – The code is well tested and generated by the ORM and only a developer can understand the code perfectly.

Q14). What is the J2EE web container like?

A defined interface that is generally intended to support the component and is referred to as the container in J2EE exists between the component and the low-level platform.

Q15). What does the term "connection pooling" mean?

Reusing old connections is made easier using the concept of connection pooling. To put it another way, if object connections are previously specified and connected, they can be reused anytime a need arises rather than having to be created from scratch.

 Q16). What is Spring Framework and discuss its benefits?

To reduce the overall complexity of an enterprise application, the open source Spring Framework is used. The major benefits of any spring Framework include –

The middle tier objects can be managed more efficiently.

The properties can be initialized quickly.

The testability of the application is made easier with injection dependencies.

The containers are lightweight and components are defined clearly.

The Spring services are managed or configured in the runtime environment instead of focusing on its architectural layer.  

 This is how you should answer the Java J2EE interview question asked during the interview, be detailed and confident.

Q17). What are the different types of collections in Hibernate?

A collection is defined as one-to-many references. The most popular collections in Hibernate include – Array, List, Set, Map, or Bag types.

Q18). What is a thin client?

A program that doesn’t have any complex operations like connection, business rules or database queries is termed as the thin client.

Q19). Define the servlet?

Servlet is a server-side component that offers full functionalities to create a server-side program. The different servlets are available with a specific design for a variety of protocols.  Most popular type of protocol for the servlet is HTTP.

Q20). Name the different phases of servlet lifecycle?

Class Loading Phase, Instantiation Phase, Initialize Phase, Removal Phase, and the Request Handling Phase.

Q21). What is JSF?

JSF is an acronym for Java Server Faces. It is the framework for designing user interfaces (UIs) for Java Web applications. With JSF, a collection of reusable UI components is included. Model-View-Controller (MVC) design principles and patterns have also been the foundation of JSF. JSF also handles the automated data saving from the form to the server and client-side presentation.

Q22). Why is a hashtable used?

A collection-synchronized object is a hashtable. It does not allow duplicate values but does allow null values. Similar to a hashmap, a hashtable.

Q23). Which JSP tags go under which categories?

There are four different categories of JSP tags, to be precise. Below is a list of them:

• Directives

• Declarations

• Scriptlets

• Expressions

Q24). What is the action form?

The term "action form" refers to a Java bean connected to a single or many action mapping. When data is entered from the client side via a UI, action form objects are immediately filled out at the server end (UI). Action forms are responsible for managing the session states of a web application.

Q25). What is an ID URL?

The textual identifier for any item of material on the World Wide Web is called a URL, which stands for Uniform Resource Locator (www). The URL's general structure is as follows:

http://host/local information

protocol is used to fetch the item (example: HTTP, FTP)

Host - The targeted host's Internet domain name.

The protocol handler on the remote host is given local information in the form of a String. It frequently consists of a file name and an extension.

Q26). What are the EJB container's system services?

The system services that are provided by EJB Container are as follows:

• Persistence

• Security

• Transaction

• Connection pooling

• Component lifecycle management

• Threading

Q27). What is the definition of the expression element? 

The expression elements used to write dynamic material back to the client browser go by that name.Make sure to prepare for these types of Java J2EE interview question to crack your interview at the first attempt.

Q28). What is the JSP directive?  

The JSP directive is a means for giving web containers metadata data about the JSP file. This Metadata is used by the web container during the JSP life cycle phases of translation and compilation.

Q29). What various JSP directive types are there?

There are three main JSP directive kinds that are available. Which are-

• Page directive

• Include directive

• Taglib directive

Q30). What happens if the connection pool that connects the Java programme to the database fails unexpectedly?

The Java programme contains active connections that would be cut off if the database went down since it makes use of a connection pool. There will be a Socket exception when the queries are run to retrieve or alter the data. Make sure to prepare for these types of Java J2EE interview question to crack your interview at the first attempt.

Q31). Describe the database independence of Hibernate.

Only the complete property database can be changed. You must prepare such shorter form of Java J2EE interview question. 

Q32. What is spring? 

In addition to providing a cogent framework for J2EE application development, which is primarily based on the IOC (inversion of control) or DI (dependency injection) design pattern, Spring is a lightweight open source framework for the development of enterprise applications that addresses the complexity of enterprise application development. Make sure to prepare for these types of Java J2EE interview question to crack your interview at the first attempt.

Q33). What are the benefits of using Spring?

Programming on a Pojo platform promotes component reuse.

Boost productivity to cut the cost of development.

Dependency Testability can be increased by using injection.

Without the need for the pricey application server, Spring needed enterprise services.

It enhances maintainability and lowers coupling in the code.

Q34). What are the advantages of the Spring Framework?

portable container

Your intermediate tier objects can be organized by Spring efficiently.

Property initialization is simple. It is considerably simpler to unit test application code when there is no need to read from a properties file.

Lazily built objects with Singleton configuration

The configuration management features of Spring are applicable to any architectural layer and any runtime environment.Make sure to prepare for these types of Java J2EE interview question as it is one of the challenging Java j2ee interview question and answers for senior developers. 

Q35). Why is Java not entirely object-oriented?

Java is not entirely object-oriented since it uses eight primitive data types that are not objects, such as boolean, byte, char, int, float, double, long, and short.

Q36). In Java, what are wrapper classes?

Java primitives are converted into reference types through wrapper classes (objects). There is a class for each primitive data type. Because they "wrap" the primitive data type into an object of that class, these are referred to as wrapper classes. Please see the graphic below, which shows several primitive types, wrapper classes, and function Object() { [native code] } arguments.

These are the most frequently asked j2ee interview questions and answers for senior developers 

Q37). When can the super keyword be used?

The super keyword in Java is a reference variable that points to an object of an immediate parent class.

When you create an instance of a subclass, you also create an instance of the parent class, to which the super reference variable refers.

The Java super Keyword has the following uses:

Use super to refer to a class instance variable's immediate parent.

The method of an immediate parent class can be called using the term super.

To call the function Object() { [native code] } of the immediate parent class, utilize the super() method.Make sure to prepare for these types of Java J2EE interview questions and answers for senior developers. 

Q38).What information does the web module include?

The following is included in the web module:

JSP files (Java Server Pages)

Servlet class files and Web deployment descriptor

files in the GIF and HTML (Hypertext Markup Language) formats

Q39).What does adapt module contain?

These are among the components of the resource adapter module:

• Java interfaces

• Classes

• Native libraries

• Other documentation

• Resource Adapter deployment descriptor

Q40). How does action mapping work?

A user can provide an action class for a specific URL, or path, and a separate target view, or the destination to which the request-response is forwarded, in action mapping. A request's mapping to an instance of a certain Action class is defined by the ActionMapping, which is information that the ActionServlet is aware of. The Action class execute() method receives the mapping, making it possible to retrieve this data directly.

Q41). What is the build file? 

An XML file with one or more asant targets is referred to as a build file. A target is a list of assignments that a user hopes to complete. A user can specify which target should be executed when asant is started. If there isn't a target, the project's default target is carried out.Make sure to prepare for these types of Java J2EE interview question to crack your interview at the first attempt.

Q42). How would you define business logic?

The code that contains an application's functionality is known as business logic. This logic is implemented in the EJB (Enterprise JavaBeans) architecture by the enterprise bean's methods.

Q43). What do you mean by "Connector"? Describe the Connector Architecture.

A connector connects containers to enterprise information systems and is a common expansion mechanism for containers. It is particular to an enterprise information system and includes application development tools for connecting enterprise information systems as well as a resource adapter. Through its support for system-level contracts, which are outlined in the Connector architecture, the resource adapter is connected to a container.

The connector architecture is a design for integrating J2EE products with enterprise information systems. An architecture for connectors includes:

A resource adaptor provided by a vendor of business information systems. This resource adapter can be plugged into a J2EE product.One of the most challenging Java J2EE interview question is this one since so many candidates don't pay attention to it.

Q44). What do you mean by the component contract? 

The component contract is the agreement made between the J2EE component and its container. This kind of contract consists of:

• Management of the component's lifecycle

• An interface that an instance uses to access different data and services from its container

• A list of the services each container is required to offer to its constituents.

Q45). Describe JNDI, JMS, and JTA.

For the purpose of coordinating and managing transactions throughout the corporate information system, JTA stands for the Java Transaction API.

Data from directory services can be accessed via JNDI, which stands for Java Naming Directory Interface. The messaging system for receiving and sending messages is known as a messaging system, and JMS stands for Java Messaging Service.

These are the most frequently asked j2ee interview questions and answers for senior developers .

Other Related J2EE Interview Questions

These are some links that you can refer to on topics related to J2EE questions and answers. Do check them out. 

1. Java Interview Questions

2. Core Java Interview Questions

3. Angularjs Interview Questions

4. Spring MVC Interview Questions

5. Hibernate Interview Questions

Conclusion

J2EE establishes standards and specifications for a number of different parts, including e-mailing, database connectivity, security, XML parsing, CORBA communication, etc., that aid in the creation of sophisticated, dependable, secure, and distributed servlets and client-server applications. It offers a number of API interfaces that serve as standards for vendor adapters from various companies and J2EE components. This makes sure that vendor programmes are not a dependency of the application components. As a result, J2EE has gained enormous popularity among Java developers working in the software industry. New learners might be curious about ‘how I should start my career in Java development?’ to level up your career growth. You can enroll yourself in Java Online Training to level up your career prospects. We hope these java j2ee interview questions help you in your upcoming interviews.  Best wishes!