JAVA/J2EE interview Questions

Core Java Interview Questions

1. Can we call finalize() method?
2. Can we declare an anonymous class as both extending a class and implementing an interface?
3. How Observer and Observable are used?
4. What are the differences between boolean & operator and  & operator
5. What are transient variables in java?
6. What are Wrapper Classes?
7. What is an abstract method?
8. What is List interface?
9. What is synchronization
10. What is the difference between yield() and sleep()?
11. What is the difference between  time slicing and  preemptive scheduling ?
12. What is the initial state of a thread when it is created and started?
13. What is the use of the finally block?

JSP Servlets

1. Difference between GET and POST
2. What are the different ways for session tracking?
3. What is difference between custom JSP tags and beans?
4. What is servlet context?
5. What is servlet mapping?
6. What is session?
7. What is the difference between JSP and Servlets?
8. What mechanisms are used by a Servlet Container to maintain session information?

EJB (Enterprise Java Bean) Interview Questions

1. What is EJB?
2. What are different types of entity beans?
3. What are different types of session bean?
4. What are the different type of Enterprise JavaBeans?
5. What is a Stateful Session bean?
6. What is abstract schema?
7. What is an Entity Bean?
8. What is BMP (Bean managed persistence)?
9. What is CMP (Container Managed Persistence)?
10. What is Session Bean?
11. What is stateless session bean ?
12. When to use a stateless session bean?
13. When to Use Session Beans?
14. When to use Stateful session bean?
15. When we should use Entity Bean ?

JMS interview questions

1. What are the advantages of JMS?
2. What are the different parts of a JMS message?
3. What is asynchronous messaging?
4. What is Byte Message?
5. What is JMS?
6. What is Map message?
7. What is messaging?
8. What is object message?
9. What is Stream Message?
10. What is synchronous messaging?
11. What is text message?
12. What is the difference between Byte Message and Stream Message?
13. What is the difference between queue and topic?
14. What is the Role of the JMS Provider?
15. What type messaging is provided by JMS

JDBC interview questions

1. What is JDBC Driver?
2. What is JDBC?
3. What are stored procedures?
4. How do you handle your own transaction?
5. Is the JDBC-ODBC Bridge multi-threaded?
6. What are the different JDB drivers available?
7. What are the steps required to execute a query in JDBC?
8. What does Class.forName return?
9. What is a ResultSet?
10. What is cold backup, hot backup, warm backup recovery?
11. What is Connection pooling?
12. What is Connection?
13. What is DriverManager?
14. What is the advantage of denormalization?
15. What is the fastest type of JDBC driver?

General Questions

1. Can a method be static and synchronized?
2. Can an application have multiple classes having main method?
3. Can I have multiple main methods in the same class?
4. Describe the principles of OOPS
5. Difference between == and equals method
6. Expain the reason for each keyword of public static void main(String args[])?
7. Explain the Encapsulation principle.
8. Explain the Inheritance principle.
9. Explain working of Java Virtual Machine (JVM)?
10. How can I swap two variables without using a third variable?
11. How can one prove that the array is not null but empty?
12. How is it possible for two String objects with identical values not to be equal under the == operator?
13. How to convert String to Number in java program?
14. If you’re overriding the method equals() of an object, which other method you might also consider?
15. In System.out.println(), what is System, out and println?
16. What are different types of access modifiers?
17. What are Java Access Specifiers?
18. What are the differences between == and .equals()?
19. What do you understand by a variable?
20. What do you understand by casting in java language? What are the types of casting?
21. What do you understand by downcasting?
22. What do you understand by numeric promotion?
23. What if I write static public void instead of public static void?
24. What if the main method is declared as private?
25. What is a native method?
26. What is a static method?
27. What is Byte Code?
28. What is data encapsulation?
29. What is difference between String and StringTokenizer?
30. What is explicit casting?
31. What is implicit casting?
32. What is meant by pass by reference and pass by value in Java?
33. What is phantom memory?
34. What is reflection API? How are they implemented?
35. What is the difference between a while statement and a do statement?
36. What is the first argument of the String array in main method?
37. What is the Java Virtual Machine (JVM)?
38. What is the Locale class?
39. What is the ResourceBundle class?
40. What is the SimpleTimeZone class?
41. What type of parameter passing does Java support?
42. What would you use to compare two String variables - the operator == or the method equals()?
43. When is static variable loaded? Is it at compile time or runtime? When exactly a static block is loaded in Java?
44. Which class is the superclass of every class?
45. Why oracle Type 4 driver is named as oracle thin driver?
46. Why there are no global variables in Java?

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