Answer 1

toUpperCase: Returns the character in upper case.

Example/
char A = Character.toUpperCase('a');
// A

isUpperCase: Returns true if the character is in upper case. Otherwise, returns false.

Example/
boolean B = Character.isUpperCase('b');
// False

Answer 2

I wasn't sure if UpperCase(char) exists so I assumed you meant to say isUpperCase(char).

Do you know what class UpperCase(char) is from? The Character and String class do not have such a method.