A data structure to store trees with an arbitrary number of children at each node is: public class TreeNode / Integer data, TreeNode firstChild; TreeNode nextSibling / Write a recursive Java method to return the leaf node with minimum value given the root of the tree. All elements are unique and if there are no leaf nodes you should return null. Your method signature should be:

Write a program that keeps asking the user for new values to be added to a list until the user enters 'exit' ('exit' should not be added to the list). these values entered by the user are added to a list we call 'initial_list'. then write a function that takes this initial_list as input and returns another list with 3 copies of every value in the initial_list. finally, inside print out all of the values in the new list. for example: input: enter value to be added to list: a enter value to be added to list: b enter value to be added to list: c enter value to be added to list: exit output: a b c a b c a b c note how 'exit' is not added to the list. also, your program needs to be able to handle any variation of 'exit' such as 'exit', 'exit' etc. and treat them all as 'exit'.