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Interview Questions and Answers

`forward()` transfers control to another resource on the server without the client knowing. The URL in the browser remains the same. `redirect()` sends an HTTP redirect response to the client, causing the client to make a new request to the specified URL. The URL in the browser changes.

Session management can be implemented using the `HttpSession` object, which allows you to store and retrieve user-specific data across multiple requests. Cookies or URL rewriting can be used to maintain the session ID.

Common J2EE design patterns include MVC, DAO (Data Access Object), Factory, Singleton, and Intercepting Filter. These patterns help to improve code reusability, maintainability, and scalability.

An Application Server provides the runtime environment and services needed to run J2EE applications. It manages resources, handles security, and provides transaction management, among other things.

A WAR (Web Application Archive) file is a package that contains all the components of a web application, such as Servlets, JSPs, and static files. An EAR (Enterprise Archive) file is a package that contains one or more WAR files, EJB modules, and other resources for an enterprise application.

MVC is a design pattern that separates an application into three interconnected parts: Model (data), View (user interface), and Controller (handles user input and updates the model/view). In J2EE, Servlets or JSPs can act as Controllers, JSPs or other presentation technologies as Views, and EJBs or Java Beans as Models.

A deployment descriptor (web.xml) is an XML file that configures the web application, defining servlets, filters, listeners, and other settings. Its used by the web container to deploy and manage the application.

Exceptions can be handled using try-catch blocks, custom error pages (configured in web.xml), and exception handling servlets or filters. Its important to log exceptions and provide meaningful error messages to the user.

J2EE filters are components that intercept requests and responses to perform tasks such as authentication, logging, request modification, and response compression.

EJBs (Enterprise JavaBeans) are server-side, reusable components that encapsulate business logic. Types include Session Beans (stateless, stateful), Message-Driven Beans (asynchronous messaging), and Entity Beans (represent data in a database, deprecated in later versions).

Stateless Session Beans do not maintain client-specific information between method calls. Stateful Session Beans maintain client-specific state across multiple method calls within a session. Stateless beans are generally more scalable.

JMS (Java Message Service) is an API for sending and receiving messages asynchronously. Its used for enabling communication between different applications or components, typically using a message queue or topic.

JDBC (Java Database Connectivity) is an API for connecting to and interacting with relational databases. It provides a standard way to execute SQL statements and retrieve data from databases.

JNDI (Java Naming and Directory Interface) is an API for accessing naming and directory services. Its used to look up resources, such as data sources, message queues, and other components, by name.

Java SE (Standard Edition) is for developing general-purpose applications, while J2EE (Enterprise Edition) is specifically designed for developing enterprise-level applications, including web applications, services, and distributed components. J2EE builds upon Java SE and adds libraries and specifications relevant to enterprise needs.

A J2EE container provides runtime environment, services and lifecycle management for J2EE components. There are three types: Web container (for Servlets and JSPs), EJB container (for Enterprise JavaBeans), and Application Client container (for client applications).

A Servlet is a Java programming language class that is used to extend the capabilities of servers that host applications accessed by means of a request-response programming model. Often used to implement web applications.

JSP (JavaServer Pages) is a technology that allows you to create dynamic web pages. It works by embedding Java code snippets within HTML pages. When a JSP page is requested, the JSP container compiles it into a Servlet and then executes the Servlet to generate the HTML response.

J2EE (Java 2 Platform, Enterprise Edition), now known as Jakarta EE, is a platform-independent, Java-centric environment for developing, building, and deploying enterprise applications. Core components include Servlets, JavaServer Pages (JSP), Enterprise JavaBeans (EJB), Java Message Service (JMS), and Java Database Connectivity (JDBC).

Advantages include platform independence, scalability, robustness, security, standardized APIs, and simplified development due to container management of resources.

Java - Java Standard Edition is normally used for developing desktop applications, it forms the core API. These standalone desktop applications do not need server.

J2EE - Java Enterprise Edition was originally known as Java 2 Platform

J2EE is a platform-independent well-documented, standards-based framework used for developing and running distributed, multi-tier, component-based Java applications.

This framework handles low-level complexity of the application, such as remote con

Client-tier components run on the client machine.

Web-tier components run on the Java EE server.

Business-tier components run on the Java EE server.

Enterprise information system (EIS)-tier software runs on the EIS server.

Containers are the interface between a component and the low-level platform-specific functionality that supports the component. Before a web, enterprise bean, or application client component can be executed, it must be assembled into a Java EE module and

JavaServer Pages (JSP) is a Java standard technology that enables you to write dynamic, data-driven pages for your Java web applications. JSP is built on top of the Java Servlet specification, whereas used Java Server Faces (JSF), a Java-based web applic

Applets, Application clients, Java Web Start enabled clients, and Wireless clients.

Applets are GUI components that typically execute in a web browser, but can execute in a variety of other applications or devices that support the applet programming model.

Servlets are faster as compared to JSP, as they have a short response time. The first step in the JSP lifecycle is the conversion of JSP to Java code and then the compilation of the code. JSPs are easier to code when compared to Servlets.

Servlet s

J2EE is a specification for a framework built to run on the JRE and written in the Java language.

A thin client is a computer system that runs on a server based computing environment. They are more secure than thick client systems. A thick client is software that implements its own features. It may connect to servers but it remains mostly functional w

The POJO class is an object class that encapsulates the Business logic.

There are a lot of Java frameworks such as Java Server Faces (JSF), Maven, Hibernate, Struts, and Spring.

The core features of the Spring architecture is used for developing any Java project, it enhances the way that developers write and deliver i

Serialization in the context of Java refers to the process in which a Java code object is systematically converted into a Byte Stream. This is done to enable the efficient transfer of the said object code from one Java virtual machine to another. Serializ

Object-Relational Mapping (ORM) is the process of converting Java objects to database tables. In other words, this allows us to interact with a relational database without any SQL.

The servlet is initialized by calling the init() method. The servlet calls service() method to process a clients request. The servlet is terminated by calling the destroy() method.

SSL(Secure Socket Layer) ensures the data that is transferred between a client and a server remains private. This protocol enables the client to authenticate the identity of the server.

JSP directives are the messages to JSP container. They provide global information about an entire JSP page.

System Analysis is a method in which facts are gathered and interpreted, problems are defined and a system is decomposed into it's components. Design emphasizes a conceptual solution that fulfills the requirements, rather than it's implementation. Systems

The steps of the design process include: Identify the need, Research. Brainstorm. Develop possible solutions. Construct a prototype. Test and evaluate. Revisions. Completion.

State- This is a value on an objects attribute at a given time. Behavior- This defines the behavior of the object, and their reactions. Identity- An object has an identity characterizing it's very life. The identification allows any object to be identifie

They are abstraction, encapsulation, inheritance, and polymorphism.

An interaction model is a design model that ties an application together in such a way as to benefit it's target users conceptual models. This determines how all the artifacts and behavior that are part of an application interrelate in ways that represen

Aggregation means a relationship where the child can exist independently of the parent. Composition insinuates a relationship where the child can not exist independently of the parent.

Relate with a project you have done.

The data structure is a data collection, management and storage system that allows for easy access and alteration. More specifically, the data structure is the set of data values, the relationship between them and the functions or operations that can be a

In a linear data structure, the data elements are organized in a linear order where every element is connected to it's previous and next adjacent elements. For a non-linear data structure, the data elements are hierarchically connected.

Traversing - access each data item exactly once; Searching - is used to find the location of one or more data items that fulfill the condition; Inserting - is add new data items to the given list of data items; Deleting -  is to remove a particular data i

Algorithm - is a procedure for solving a problem, based on conducting a sequence of specified actions. A computer program can be viewed as an elaborate algorithm.

Greedy Algorithms - is algorithm that follows the problem-solving heuristic

The most fundamental types of algorithm are: Recursive Algorithms, Dynamic programming algorithm, Backtracking algorithm, Divide and Conquer Algorithm, Greedy Algorithm, Brute Force Algorithm.

Recursion is a method used to allow a function call it'self. This technique offers a way to break down complicated problems into simple problems that are easier to solve.

Explain specific instances with respect to the job JD.

Model–view–controller(MVC) is a software design pattern used for developing user interfaces that separate the related program logic into three interconnected elements. Each of these components is built to handle specific development aspects of an applicat

Explain specific instances with respect to the job JD.

(1) Choose the Right Technology when picking up a programming language, Database, Communication Channel.

(2) The ability to run multiple servers and databases as a distributed application over multiple time zones.

(3)Database backup, correcti

Object-oriented programming is a programming paradigm based on the concept of \"objects\", which can contain data, in the form of fields, and code, in the form of procedures. A feature of objects is that objects' own procedures can access and often modify

Most modern development processes can be described as agile. Other methodologies include waterfall, prototyping, iterative and incremental development, spiral development, rapid application development, and extreme programming.

Software Development Life Cycle (SDLC) is a process used to design, develop and test high-quality software. Also referred to as the application development life-cycle.

Software testing is called the process or method of identifying errors in an application or system, such that the application works according to the requirement of end-users. It is an examination carried out to provide users the information on the quality

Explain specific instances with respect to the job JD.

A good software engineer is someone who is not only competent to write code but also competent to create, produce and ship useful software.

The primary aim of the code review is to ensure that the codebase overall product quality is maintained over time. It helps give a fresh set of eyes to identify bugs and simple coding errors. All of the tools and processes of code review are designed to t

Use a phased life-cycle plan, Continuous validation, Maintain product control, Use the latest programming practices, Maintain clear accountability for results.

Software engineering always requires a fair amount of teamwork. The code needs to be understood by designers, developers, other coders, testers, team members and the entire IT team.

Schedule, Quality, Cost, Stakeholder Satisfaction, Performance

A software project manager determines the project specifications, builds the project team, draws up a blueprint for the whole project outlining the scope and criteria of the project, clearly communicates the project goals to the team; allocates budget, an

The most common software sizing methodology has been counting the lines of code written in the application source. Another approach is to do Functional Size Measurement, to express the functionality size as a number by performing Function point analysis.

The major parts to project estimation are effort estimation, cost estimation, resource estimate. In estimation, there are many methods used as best practices in project management such as-Analogous estimation, Parametric estimation, Delphi process, 3 Poin

software configuration management (SCM) is the task of tracking and controlling changes in the software code, part of the larger cross-disciplinary field of configuration management. Whereas change management deals with identification, impact analysis, d

Basecamp, Teamwork Projects, ProofHub, Zoho Projects, Nifty, Trello, JIRA, Asana, Podio, etc.

A feasibility study is a study that takes into account all of the related factors of a project — including economic, technological, legal, and scheduling considerations — to assess the probability of completing the project.

Functional requirements are the specifications explicitly requested by the end-user as essential facilities the system should provide. Non-functional requirements are the quality constraints that the system must satisfy according to the project contract,

Pseudocode is an informal high-level explanation of the operating principle of a computer program. It uses the structural conventions of a normal programming language but is intended for human reading rather than machine reading.

Validation is the process of checking whether the specification captures the user's needs, while verification is the process of checking that the software meets the specification.

Different Types Of Software Testing - Unit Testing, Integration Testing, System Testing, Sanity Testing, Smoke Testing, Interface Testing, Regression Testing, Beta/Acceptance Testing.

Quality control can be described as part of quality management that is focused on fulfilling quality requirements. While quality assurance relates to how a process is performed or how a product is made.

Single Responsibility Principle (SRP), Open/Closed Principle (OCP), Liskov Substitution Principle (LSP), Interface Segregation Principle (ISP), Dependency Inversion Principle (DIP).