Possible-Java-Interview-Questions

Basic Java

1. Difference between JDK,JRE and JVM?
2. What is Synchronization?
3. Difference between processes and threads?
4. What are Wrapper classes? Boxing and Autoboxing? Why?
5. What purpose does the keywords final, finally, and finalize fulfill?
6. Difference between StringBuilder and StringBuffer?
7. What are the differences between Heap and Stack Memory?
8. What is the difference between ArrayList and Vector?
9. What is the difference between HashMap and HashTable?
10. What is the difference between equals() and == operator?
11. What is compile time and runtime?
12. Java 8 Features compared to previous versions?
13. Java 17 Features compared to previous versions?
14. HashMap and TreeMap Difference?
15. Difference between throw and throws keyword in Java?
16. Write a program to reverse the String?
17. Write a program to sort a HashMap data?
18. What is Type?

OOP

1. Difference between abstract Class and interface?
2. What is Polymorphism?
3. What is runtime polymorphism or dynamic method dispatch?
4. What is the difference between overriding and overloading?
5. Can you override a private or static method in Java?
6. What is Dependency Injection?
7. Can a Constructor be made static? What happens?
8. Types of Inheritance?
9. What are immutable objects?
10. Why is String immutable?

XML and JSON

1. How to convert XML to JSON?

Servlets, JSP

1. What is JSP? Why should we use it?
2. Prepared Statement?
3. JSP tags?

Spring

1. Setter Injection?
2. Constructor Injection?
3. Why use Annotation in Spring?
4. Named Query Hibernate?
5. What is Spring Bean?
6. What is SessionFactory?
7. Dependency Injection in Spring?
8. What is ORM? Why should we use it?
9. Explain Spring Bean Life Cycle?
10. What are @Scope in Spring?
11. Difference between Entity and DTO?

MySQL or Database

1. Create Table
2. ALTER Table