/** * Returns the character that occurs most frequently in * the given string. If several characters occur with * the same maximum frequency, returns the one that * occurs first in the string. The string must be nonempty. * 
 * For example, given the string "banana" the method returns 'a'. * Given the string "abcbcbbcca" the method returns 'b'. * @param s * nonempty string * @return * most frequently occurring character in s */ public static char findMostFrequentCharacter(String s) { // TODO return 0; }