Q. Write code to list duplicates elements from an array Q. Find 3rd max salary of employee table Q. Find salary of employees not equal to 20000 Q.what is OOPS concept. Q. What is polymorphism and why we need same name method. Q. What is abstract class and interface Q. Why we need interface in java. Q. What is hashmap .give implementation of hashmap. How it is different from hashtable. Q. Which collections is best when we want thread safe. Q. What is set and hashmap. Q. What is static? Define each static method,static variable and static class. Q. What is immutable.
