1. Use ListIterator to print collection in forward direction and reverse direction.
2. Find the number of duplicate elements in collection
3. Arrange numbers in collection in descending order
4. Sort the list of numbers in ascending order using comparable interface and compareTo method.
5. Create an List with custom class object and store students details in it and do the following
	->sort the list in ascendnig order based on students rollno
	->sort the list based on students name
	->filter the students who has paid complete fees
	->filter the students studying core-java
	->Give discount of 1000rs to the students studying core-java
	->Find the total amount of fees paid by core java students.(use filter,map and also reduece) 
6. Create an containsIgnoreCase() method.