1) Write a method which is passed a String which returns true if the String contains a double letter or falseotherwise.

2) Write a method which is passed a String. It returns the index of the last Roman Numeral (recall that the Roman Numerals are {'I', 'V', 'X', 'L', 'C', 'D', 'M'}) found in the String or -1 if no Roman Numeral is found in the String.

3) Write a method which is passed a String s and returns a new String that's the same as s, but with the first letter of each word capitalized. There is a static method in the Character class toUpperCase that is passed a char c. If c is a lower-case letter, it returns its upper case equivalent. If it's not a lower-case letter, it returns c.

4) Write a method appendIfMissing which is passed a String s and a String e (for ending). If s doesn't already end with e, the method returns a new String which consists of the contents of s concatenated with e. It returns s otherwise. For example, if s refers to the String "lightningbug" and e refers to the String "bug", the method returns "lightningbug". If s refers to the String "Airplane II", and e refers to the String ": the Sequel", the method returns "Airplane II: the Sequel".