- Published on
Java Fundamentals
- Authors
- Name
- Lucian Oprea
- @LucianDSA_
00:30:00
Language Basics
⏷ 1. How do you make a class Immutable in java? How about pass by reference issue?
⏷ 2. What is the importance of hashCode() and equals() methods?
⏷ 3. Is Data Passed by Reference or by Value in Java?
⏷ 4. Nested classes can be static or non-static (Inner Class). How do you decide which to use? Does it matter?
⏷ 5. What are static initializers and when would you use them?
⏷ 6. What is the difference between == and equals() in Java?
⏷ 7. What happens if you assign a long to an int? How would you handle such a situation in Java?
⏷ 8. What’s the difference between a checked and unchecked exception? Can you explain with examples of each?
⏷ 9. What is the difference between the Comparable and Comparator interfaces
⏷ 10. What Is a ClassLoader?
⏷ 11. What Is the purpose of the Serializable interface?
⏷ 12. What happens if there is no break in a switch statement?
Strings and Text Processing
⏷ 13. Why are Strings immutable in Java, and when would you prefer StringBuilder over String?
⏷ 14. Reverse a String without using any library method
⏷ 15. Validate an Email Address using Pattern and Matcher
⏷ 16. How would you read a file line by line in Java?
Exceptions and Errors Handling
⏷ 17. What happens if there is a return statement in the try block and the finally block?
⏷ 18. What is the difference between Exception and Error in Java?
⏷ 19. Can you explain the hierarchy of exceptions in Java?
⏷ 20. What happens if an Exception is thrown in a static block?
⏷ 21. How do you create a Custom Exception in Java? When it’s useful?
⏷ 22. What are best practices for exception handling in Java?
⏷ 23. What is a NullPointerException, and how can you prevent it?
⏷ 24. How do you handle exceptions in a multi-threaded environment?
Generics and Type Safety
⏷ 25. What is the difference between ? extends and ? super in generics?
⏷ 26. How do you create a generic method in Java?
⏷ 27. Can you explain the purpose of the T, E, K, and V placeholders in generics?
⏷ 28. Write a program to create a generic class for a simple stack implementation.
Memory Management
⏷ 29. What is the Java memory model, and how is memory divided in the JVM?
⏷ 30. What is the difference between stack memory and heap memory?
⏷ 31. What is garbage collection in Java, and why is it important?
⏷ 32. What is a memory leak in Java, and how can it occur despite garbage collection?
⏷ 33. To avoid memory leaks why is best practice to avoid unnecessary static references.
⏷ 34. How can you use WeakHashMap for Automatic Cleanup?
⏷ 35. What are OutOfMemoryError and StackOverflowError, and how do you handle them?
⏷ 36. What is the purpose of the finalize() method, and why is it discouraged?
⏷ 37. What tools or techniques can you use to analyze and optimize memory usage in Java?
Functional Programming
⏷ 38. What is the purpose of the @FunctionalInterface annotation?
⏷ 39. How do Predicate and Function differ in Java?
⏷ 40. How can you use method references to simplify code with lambda expressions?
⏷ 41. What is the purpose of the Optional class? Provide multiple examples.
Date and Time API
⏷ 42. What are the main differences between Date and LocalDate in Java?
⏷ 43. How do you format a LocalDateTime object to a specific pattern?
⏷ 44. How do you calculate the difference between two dates in Java 8?
⏷ 45. How do you convert a legacy Date object to a LocalDate?
Reflection and Annotations
⏷ 46. What is Reflection? Give an example of functionality that can only be implemented using reflection.
⏷ 47. What are the different retention policies for annotations?
⏷ 48. How do you create a custom annotation in Java?
New features in Java 11 & Java 17
⏷ 49. What are the new String methods introduced in Java 11, and how do they differ from Java 8?
⏷ 50. What is the purpose of the var keyword introduced in Java 10, and is it available in Java 8?
⏷ 51. How does the new HTTP Client API in Java 11 improve over the HTTP libraries used in Java 8?
⏷ 52. What new features in sealed classes introduced in Java 17 make them different from regular inheritance models in Java 11?
⏷ 53. What are the improvements in pattern matching in Java 17 compared to Java 11?
⏷ 54. How does Java 17 improve text blocks compared to Java 11?
⏷ 55. What are records, and how do they differ from regular Java classes?