70+ Java and J2EE Interview Questions
Demonstrating your J2EE knowledge in a Java interview can be critical to landing a developer position at a top-tier or FAANG+ company. J2EE is one of the most popular platforms used by Java developers to simplify the development and deployment of enterprise-level applications that can run on a variety of Java-supported platforms.
You can make a good impression by scanning Java and J2EE interview questions beforehand and preparing accordingly. Read on to learn about the types of J2EE interview questions asked in coding interviews and how to answer them.
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In the below sections, we have provided a list of basic and advanced Java and J2EE interview questions that will help you nail your Java interview. In this article, we’ll cover:
- Basic Java and J2EE Interview Questions
- Advanced Java and J2EE Interview Questions
- Java and J2EE Interview Questions on Design Patterns
- Miscellaneous Java and J2EE Interview Questions
- FAQs on Java and J2EE Interview Questions
Basic Java and J2EE Interview Questions
Some of the basic Java and J2EE interview questions and answers are as follows:
Q1. What’s the difference between JVM Spec, JVM Runtime, and JVM Implementation?
JVM spec is simply the specification of JVM. JVM implementation is the actual implementation of JVM by vendors. Meanwhile, JVM runtime is a running program supporting Java specified programs.
Q2. What is JIT?
The Just-in-Time compiler improves the performance of Java apps by combining platform-neutral bytecode to the native machine code during run time.
Q3. What are JRE and JDK?
JDK is a kit providing an environment to execute and develop the Java program. On the other hand, JRE is a kit that provides an environment to run (not develop) the Java program.
Q4. Define Locale.
A locale object shows a specific political, cultural, or geographical region. An operation that requires locale is called locale-sensitive.
Apart from these, do prepare for the below Java and J2EE interview questions as well:
- What is a ResourceBundle class?
- Can you force a garbage collector? How does it decide which objects need to be removed?
- How can you obtain platform-dependent values, such as path separator or line separator?
- Mention the methods in the object.
- What is the final keyword denoting w.r.t. class, variable, and method?
- Are you able to instantiate math class?
- Can you declare the main method as final?
- Mention the difference between getclass and instanceof. Are they the same or not?
- Do you know whether Java provides any construct to determine an object’s size?
- Define native method.
- Is it okay for a Java file to have more than one Java class?
- Is an empty Java file a valid source?
- Mention the difference between a parameter and an argument.
- Mention the various scopes for Java variables.
- Define wrapper classes.
The interviewer also includes a few advanced-level Java and J2EE interview questions during a typical Java interview. You must take these questions seriously and prepare for them accordingly.
Advanced Java and J2EE Interview Questions
Mentioned below are a few advanced level Java and J2EE programming interview questions for senior software developers:
Q1. Define HQL.
HQL (Hibernate Query Language) is an object-oriented query language. Unlike SQL, which works on tables and columns, HQL works on persistent objects and properties. HQL is a superset of Java Persistence Query Language (JPQL). This means that all JPQL queries are valid HQL queries, but all HQL queries are not JPQL queries
Q2. What is a Java thin client?
Thin client is a lightweight client. A thin client connects to the cluster through a standard socket connection without becoming a part of the cluster topology. Thin client does not hold any data and is not used for computing calculations. It performs all operations through the standard node?.
Q3. What does URN mean?
URN is an abbreviation for Uniform Resource Name. It is a unique identifier that identifies an entity.
Q4. What are the uses of Spring?
Spring is an open-source application development framework for enterprise Java. It is one of the most widely used frameworks for Java. Developers use Spring to develop high-performing, testable, and reusable code
Q5. What are the different phases that fall under the life cycle of a servlet?
Request handling, Servlet installation, The init method, Servlet class loading, and Removal from the service.
Here are a few other Java and J2EE interview questions for experienced professionals:
- What must servlets execute?
- Do you know whether servlet is pure Java or not?
- Mention the method to create objects without using ‘new’ in Java.
- Mention the scope of default in spring.
- What are the components of the J2EE app?
- Mention the types of j2EE clients.
- Define JSF.
- What is a Hash table?
- Define hibernate.
- What is the difference between saveorupdate and save?
- Define ORM and mention a few of its benefits.
- What is the difference between the get and load method?
- Mention the core interfaces of hibernate framework.
- What file extension will you use for mapping a hibernate file?
- Mention the difference between .jar, .war, and .ear files.
Read our Top Advanced Java Interview Questions for your coding interview.
Java and J2EE Interview Questions on Design Patterns
Here are some design patterns for Java and J2EE interview questions:
Q1. What are the different components in the multi-tier architecture?
The presentation tier, Resource tier, and Business tier are the components of multi-tier architecture.
Q2. What are the different modules in Spring?
The list of spring modules is
- Aspect-oriented programming
- DAO module
- O/R mapping module
- Core container module
- Web module
- Application context module.
Q3. What is a servlet?
A servlet is a server-side component that provides development mechanisms for server-side programs. It makes use of classes available under a Java package.
Q4. Define the various phases in the life cycle of a servlet.
The different phases are:
- Servlet instantiation
- Servlet class loading
- The init method
- Removal from the service
- Request handling
Q5. Define JMS, JNDI, and JTA.
- JNDI: It is Java Naming Directory Interface. It helps access information from the directory services.
- JMS: It is a Java Messaging Service. It is responsible for receiving and sending messages through various messaging systems.
- JTA: It is a Java Transaction API. It coordinates and manages the transaction in an enterprise information system.
You can also go through the following Java and J2EE technical architect interview questions:
- Explain the terms - EDI and EAI.
- What are the roles of third-party software in the EJB framework?
- Explain the difference between load and get.
- What are the benefits of using spring for developing applications?
- Mention the different types of JSP tags.
- Briefly define SSL or secure socket layer.
- What does EJB mean? Mention the subtypes and basics of the same.
- What does the JSP directive mean? Mention the different types of JSP directives.
These Java and J2EE interview questions will assist aspiring architects in their upcoming tech interview prep. You can also take a look at some of the Top Java Programming Interview Questions and Answers.
Miscellaneous Java and J2EE Interview Questions
Apart from the above-mentioned questions, the following miscellaneous Java and J2EE interview questions might be asked by an interviewer:
Q1. What is connection pooling?
Connection pooling is a practice generally used to extract already existing connections. These connections can be used instead of generating new connections.
Q2. Define hibernate proxy.
It is an object proxy that includes the process of retrieving the objects until and unless you require them.
Q3. How will you create a SessionFactory?
Configuration cfg = new Configuration(); cfg.addResource("dir/hibernate.hbm.xml"); cfg.setProperties( System.getProperties() ); SessionFactory sessions = cfg.buildSessionFactory();
Q4. Mention the collection types in hibernate.
List, array, map, bag, set are the collection types in hibernate.
Q5. Mention the JSP tag types.
JSP tags are divided into four categories:
Go through the following additional miscellaneous Java and J2EE interview questions:
- How can you access web.xml parameters from the JSP page?
- What is the EAR file?
- Define JSP Directives.
- Define ActionErrors.
- What are struts?
- What is action mapping?
- Define ActionForm.
- What are the different spring modules?
- Define Bean Factory. Have you used it before?
- Define MCV on struts.
- What does authorization constraint and authorization mean?
- What is the difference between savings and update or save?
- Define design objectives of the J2EE architecture.
- What are the core design goals of J2EE architecture?
- What is the role of a J2EE architect?
That said, brushing up your overall skills related to Java and J2EE interview questions is of paramount importance and can help you secure your dream job in Tier-1 tech companies. You can practice some Java Interview Questions for Software Developers With 5 Years of Experience too.
FAQs on Java and J2EE Interview Questions
Q1. How much does a Java developer earn in the US?
The average annual salary of a Java developer is around $106,019 in the US.
Q2. What is the minimum eligibility to become a Java developer?
Q3. Are Java and J2EE the same?
Before appearing for Java and J2EE interview questions, you should have a common understanding of the difference between both these programming languages. J2EE is just an extension of Java SE, which is based on the Java programming language. In simple words, J2EE is a part of Java featuring a powerful library set.
Q4. What are the four types of J2EE modules?
The four types of J2EE modules are Application Client Module, WEB Module, Enterprise JavaBeans Module, and Resource Adapter Module.
Q5. What is J2EE?
J2EE stands for Java 2 Platform, Enterprise Edition. The J2EE platform is used to create multi-tier, web-based applications by utilizing a set of protocols and application programming interfaces (APIs).
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