In Java using recursion only:

Write a recursive method isBackwards that has two String parameters and returns true if the two Strings have the same sequence of characters but in the opposite order (ignoring white space and capitalization), and returns false otherwise. The method should throw an IllegalArgumentException if either String is null.

Use this method: public boolean isBackwards(String first, String second)

Test this method using the following examples:

isBackwards("Fried", "deirf") -> true

isBackwards("Sit", "Toes") -> false

isBackwards("", "") -> true

isBackwards("I madam", "mad am I") -> true