• 1. Pre-modular vs module-aware class loaders
• 2. String pool vs Constant pool vs Symbol pool
• 3. How StringBuffer differs from String
• 4. The concatenation (pooling) problem with String
• 5. Why Java doesn't support multiple inheritance
• 6. No virtual keyword in Java, and how it stays efficient
• 7. Commonly used annotations and why they exist
• 8. What are concrete classes in Java?
• 9. What is an abstract class, and when does a class become abstract?
• 10. When and where to use final, and what it does
• 11. How constructor chaining is done in Java
• 12. Accessing the parent class's methods and constructor with super
• 13. Sealed, non-sealed and final classes
• 14. Overriding toString(), and why we avoid console I/O inside class methods