1. In OOP, how does abstraction differ from encapsulation? 2. Why does Java not support multiple inheritances? 3. Will finally block execute if you put System.exit () in catch or try block? 4. How can you ensure that N threads can access N resources without deadlock? 5. Is Java pass-by-reference or pass-by-value? 6. What’s the difference between fail-fast and fail-safe? 7. Can you store null keys/ values and duplicate keys/values in a Java HashMap? 8. What do System.gc() and Runtime.gc() methods do? 9. Distinguish between throw and throws in Java