Answer a, b, c, and d of the following question:

P1.2.7 (uses Java) Using the real-Java methods from Exercise 1.2.9 above, write decision procedures in real Java for the following languages of Java strings. These methods should each take a String as argument and return a boolean. (a) The set of all strings whose third letter exists and is b.

(b) The set of all strings whose first letter exists and is the same as its last letter.

(c) The set of all strings that are palindromes (equal to their reversals).

(d) The set of all strings whose letters are in alphabetical order, like abbfgkklyz. (Java defines the order operators < and <= on characters assume that alphabetical order is defined in terms of these).

Here is 1.2.9 for reference: E1.2.9 (uses Java) The String class in real Java has instance methods char charAt(int n), giving the character in the nth position of the calling string, and int length(), giving the length of the calling string.