1. What is the Java Memory Model, and how does it affect concurrent programming?
2. Explain the concept of thread safety and how to achieve it in Java.
3. What are the different types of thread pools in Java, and how do they work?
4. How does Java's garbage collection work? Explain the different types of garbage collectors.
5. What is the purpose of the volatile keyword in Java?
6. Explain the differences between wait(), notify(), and notifyAll().
7. What are the principles of object-oriented programming in Java?
8. How do you implement a singleton design pattern in Java?
9. What is the difference between HashMap and ConcurrentHashMap?
10. Explain the concept of immutability and how it is achieved in Java.
11. What is the Fork/Join framework in Java? How does it improve performance?
12. How do you implement custom synchronization in Java?
13. What is the purpose of the java.nio package?
14. Explain the differences between the InputStream and Reader classes in Java.
15. What are the benefits of using the java.util.concurrent package?
16. What are the main features of Java 8’s Stream API?
17. How do you perform lazy evaluation with streams in Java?
18. What is the difference between map() and flatMap() in Stream API?
19. Explain the concept of method references in Java 8.
20. How do you create a custom functional interface in Java?
21. What is the difference between Function, Consumer, and Supplier interfaces?
22. How does the CompletableFuture class enhance asynchronous programming?
23. What is the significance of the @FunctionalInterface annotation?
24. How can you implement a reactive programming model in Java?
25. Explain the role of the java.util.Optional class.
26. What are the advantages of using CompletableFuture over traditional threading?
27. What is the significance of lambda expressions in Java?
28. How do you handle exceptions in lambda expressions?
29. What is the difference between synchronized methods and synchronized blocks?
30. How does the ThreadLocal class work in Java?
31. What are the different levels of access control in Java?
32. Explain the concept of reflection in Java and its use cases.
33. What are the performance implications of using reflection?
34. How do you create a proxy using Java’s Proxy class?
35. What is the Java Native Interface (JNI), and when would you use it?
36. Explain the concept of annotations in Java and their purpose.
37. What are the differences between marker annotations and single-value annotations?
38. How do you create a custom annotation in Java?
39. What is the purpose of the @Override annotation?
40. How does Java's exception handling mechanism work?