a) A college professor collects books every day over a number of days. Write in java, that asks the professor for the number of days he wishes to collect books. For each of the days, ask the professor for the number of books he collected. Calculate and display the total number of books collected. Do not allow the professor to enter a negative value for number of days and the number of books collected (hint use loops to validate entries) In all incorrect cases for input display an appropriate message and allow the professor to enter a valid valuel