6. Write Java functions (static methods) that provide the following computed mappings. Do not use Maps, just very simple functions using character arithmetics, 1-2 lines should suffice: (a) 'a' 0, 'b' 1,, 'z' 25, and also 'A' 0, 'Z' 25 (in one map) Note that Java supports arithmetic with char variables: ch - 'a' is 0 if char ch is 'a', 1 if it is 'b', and so on. (b) "aa" 0, "ab" 1, "ac" 2,,"az" 25, "ba" 26, "bb" 27,, " zz" (26261) (c) The inverse of b: input a number and return a pair of letters (in other words - reverse the directions of the arrows in b)