1. Difference between structure and class? 2. What is interface and its usage? 3. Difference between interface and abstract class? 4. Difference between value type and reference type in java? 5. What is inheritance and polymorphism? 6. What is encapsulation and abstraction and their usage? 7. What is run time polymorphism with example? 8. Difference between Java and Android? 9. What is starting point of Android? 10. Can we define two launcher activities in the same manifest? 11. Difference between implicit intent and explicit intent?