Write a JAVA method that expands a given binomial (ax + by)n, where integers a, b, n are user inputs. For example, if a = 2, b = -12, n = 4 are entered the method should print or return
program in java. Get a string from user and also validate it’s length should be at least 1. Pass this string to a method that returns a new string with the first char added at the front and end, so "cat" yields "ccatc".