Kody Technolab

Kody Technolab – Technical Round— 1. Tell me about yourself. 2. What is the difference between Spring and Spring Boot? 3. What is DI and IoC? 4. What are the types of Beans in Spring Boot? 5. What is a Transaction and @Transactional? 6. What is the difference between @Repository, @Service, and @Controller annotations? 7. How does Spring Boot know that this particular class is a Controller? 8. What is Global Exception Handling? 9. Can I create two @RestControllerAdvice files? 10. What are the Pillars of OOP? 11. What is the difference between an Abstract Class and an Interface? 12. Is Java a pure object-oriented language? 13. Why do we need Wrapper Classes? 14. What is a JWT Token? 15. What are Refresh Tokens and Access Tokens? 16. What is Token Blacklisting? 17. What is Token Rotation? 18. Code snippets were given on paper — give the output. 19. Write Java Streams code on paper. 20. What is a Functional Interface? 21. What are Lambda Functions? 22. What are Threads? 23. What are Virtual Threads and Platform Threads? 24. What is the difference between run() and start()? 25. What are Worker Threads? 26. What is the difference between s1 == s2 and s1.equals(s2)? 27. What is the String Pool? 28. What is the Collection Framework? 29. What are Fail-Fast and Fail-Safe classes? 30. What are the top main classes in the Collection Framework? Tell the difference between each. 31. What is DTO Pattern? 32. What is JDBC? 33. What are Streams? 34. Write Java code on paper to print "1" to "N" without using loops. 35. What is Swagger? 36. What is Authorization and Authentication? 37. What is the difference between ArrayList and LinkedList in terms of efficiency? 38. Is Java pass-by-value or pass-by-reference, and how? 39. A tricky code snippet was given involving try and multiple catch blocks — which catch block would be executed first? SQL: 40. Given Customer and Country tables, write a query to get all customers from India with a salary between ₹20K and ₹40K using JOIN. 41. Write a query to fetch all customers from India with a salary greater than ₹40K without using JOIN.