Determining the Type of a Character: determine the properties of a character for the entire Unicode character set.
public class Main { public static void main(String[] argv) throws Exception { char ch = 'a'; if (Character.isLetter(ch)) { // true } if (Character.isDigit(ch)) { // false } if (Character.isLowerCase(ch)) { // true } if (Character.isUpperCase(ch)) { // false } } }