Ready to ace your J2EE interview? This guide meticulously crafted from the insights of two leading online resources provides you with the ultimate arsenal of knowledge to tackle any J2EE-related question thrown your way.
Buckle up aspiring J2EE developer and embark on a journey of enlightenment!
What is J2EE?
J2EE, short for Java 2 Enterprise Edition is a robust platform for developing and deploying multi-tier web-based enterprise applications. It’s like the Swiss Army Knife of the Java world, offering a comprehensive set of services APIs, and protocols to build powerful and scalable applications.
Delving into the Core of J2EE Architecture
J2EE applications are typically built using a multi-tier architecture, consisting of:
- Client Tier: The user interface, typically a web browser or mobile app, that interacts with the application.
- Middle Tier: The heart of the application, responsible for business logic, data access, and communication between the client and server tiers.
- Backend Tier: The data storage layer, usually a relational database or a distributed file system.
J2EE Modules Building Blocks of Applications
J2EE applications are assembled from various modules, each with its specific purpose:
- Application Client Module: Contains client-side components for accessing the application.
- Web Module: Includes web components like servlets, JSPs, and static content.
- Enterprise JavaBeans (EJB) Module: Houses business logic components.
- Resource Adapter Module: Enables communication with external systems like databases or legacy applications.
Unveiling the Mysteries of J2EE Components
J2EE components are the fundamental building blocks of applications. Let’s explore some key components:
- Applets: Small Java programs embedded in web pages, adding interactivity.
- Servlets: Java programs that dynamically generate web content.
- JavaServer Pages (JSPs): A combination of Java code and static content, offering a simpler way to create dynamic web pages.
- Enterprise JavaBeans (EJBs): Reusable server-side components that encapsulate business logic and data access.
J2EE Technologies: Powering the Platform
J2EE leverages various technologies to provide a comprehensive development environment:
- Java Servlet API: Enables the creation of dynamic web content.
- JavaServer Pages (JSP) Technology: Simplifies the development of dynamic web pages.
- Enterprise JavaBeans (EJB) Technology: Provides a framework for building reusable server-side components.
- Java Message Service (JMS): Facilitates asynchronous messaging between applications.
- Java Transaction API (JTA): Manages transactions across multiple resources.
- Java Naming and Directory Interface (JNDI): Enables access to naming and directory services.
J2EE Interview Questions: Your Path to Success
Now, let’s dive into the world of J2EE interview questions, equipping you with the knowledge to impress your interviewers:
1. What is J2EE?
2. What are the main advantages of J2EE?
3. What are some of the technologies provided by the J2EE platform?
4. What are the various components of J2EE application architecture?
5. How is JDK different from JIT?
6. How are PATH and CLASSPATH different from each other in terms of J2EE?
7. How is multi-tier client-server architectural model advantageous?
8. What do you understand by build file?
9. Why do we have JDBC and JNDI in J2EE? How are they different from each other?
10. What is an EJB? How can you use it in J2EE?
11. What are the J2EE applets? Why can we use it?
12. What is the architecture model of Struts?
13. What do you understand by ORM?
14. What are the different types of J2EE modules?
15. What is a web container in J2EE?
16. What is the concept of connection pooling?
17. What do you understand by the servlet?
18. What are the main components of multi-tier architecture?
19. Explain JTA, JNDI, and JMS.
20. Explain the J2EE tiers.
21. Describe the EAR, WAR, and JAR.
22. What do you understand by Spring?
23. What are the different modules used in Spring?
24. What is action mapping?
25. What do you understand by ActionForm?
26. What is backing bean?
27. What is the build file?
28. What do you understand by business logic?
29. How will you explain CDATA?
30. What do you mean by the Component Contract?
31. What do you understand by Connector? Explain Connector Architecture.
32. What are the limitations of Hibernate?
33. What are the major benefits of hibernate?
34. Define ORM and its working in J2EE?
35. What is authorization?
36. Define authorization constraint?
37. How will you explain save() and saveorupdate() methods in hibernate?
38. How will you explain load() and get() methods?
39. What are the core interfaces of the hibernate framework?
40. What is B2b?
41. What is the file extension used for hibernate mapping file and hibernate configuration file?
42. Define a way to add Hibernate mapping file in hibernate configuration file?
43. What is considered as a web component?
44. What are the types of J2EE clients?
45. What do you understand by a word applet?
46. What is the container?
47. What is an “applet container”?
48. What do you understand by a thin client?
49. What is JavaServer Faces (JSF)?
50. What is an EJB platform?
51. What do you mean by the deployment descriptor?
52. Define the Struts in the J2EE framework?
53. Define Hashtable in J2EE?
54. Define Hibernate and HQL?
55. What is the difference between a thin client and a thick client?
56. What is the difference between a servlet and a JSP?
57. What is the difference between an EJB and a web service?
58. What is the difference between JTA and JDBC?
59. What is the difference between JNDI and LDAP?
60. What is the difference between JMS and AMQP?
61. What is the difference between Spring and Struts?
62. What is the difference between Hibernate and JPA?
63. What is the difference between a DAO and a Repository?
64. What is the difference between a SessionFactory and a Session?
65. What is the difference between a Transaction and a Unit of Work?
66. What is the difference between a Stateless EJB and a Stateful EJB?
67. What is the difference between a Local EJB and a Remote EJB?
68. What is the difference between a Message-Driven Bean and a Session Bean?
69. What is the difference between a Web Service and a RESTful Web Service?
70. What is the difference between SOAP and REST?
71. What is the difference between XML and JSON?
72. What is the difference between HTTP and HTTPS?
73. What is the difference between a GET request and a POST request?
74. What is the difference between a PUT request and a DELETE request?
75. What is the difference between a client-side cookie and a server-side cookie?
76. What is the difference between a session and a cookie?
77. What is the difference between authentication and authorization?
78. What is the difference between a role and a permission?
79. What is the difference between a user and a group?
80. What is the difference between a database and a data warehouse?
81. What is the difference between a relational database and a NoSQL database?
82. What is the difference between SQL and NoSQL?
83. What is the difference between ACID and BASE?
84. What is the difference between a transaction and a unit of work?
85. What is the difference between a lock and a latch?
86. What is the difference between a deadlock and a livelock?
What is Hibernate?
Hibernate is an open source object-relational mapping and query service. It’s possible to write HQL instead of SQL in Hibernate, which saves developers time that would have been spent writing plain SQL.
Hibernate has a more powerful association, inheritance, polymorphism, composition, and collections. It is a beautiful approach for persisting into the database using the Java objects. Hibernate also allows you to express queries using Java-based criteria.
1 What are the benefits of ORM?
- Productivity
- Maintainability
- Performance
- Vendor independence
