Java threading concepts

1) Where to use abstract class and where to use Interfaces 2) how can you avoid overrriding 3) While method overlaoding if two methods are written with the same name,parameters and same data type but different return type. Will the code complile?? 4) What are the methods to implement multithreading? What is the difference between Thread.start() & Thread.run() method? 5) Implement code for multithreading using runnable 6) How to solve deadlock situation in threads 7) What is the difference between jsp forward and redirect 8) Write a query to find the highest and second highest salary from emplyoee table. 9) Why to use hibernate 10) What are the different object states in hibernate. 11) Puzzle: In a room there are 3 switches and one of the switch will light up a bulb in other room. You can go inside the room only once. How to find the right switch.