State the data type and value of res after the following is executed: char ch = 't'; res = Character.toUpperCase(ch);

Data type: char Value: 'T'

Character.toUpperCase() takes a char and returns a char, so res is of type char and holds 'T'. The question is really about return types, which are asked every year. Group the Character methods: is... methods (isDigit, isLetter, isUpperCase) return boolean to... methods (toUpperCase, toLowerCase) return char Note that the original variable ch is unchanged — the method returns a new value rather than modifying its argument.