char ch = 'a';
 
// Unicode 字符表示形式
char uniChar = '\u039A'; 
 
// 字符数组
char[] charArray ={ 'a', 'b', 'c', 'd', 'e' };
public class Test {

    public static void main(String args[]) {
        System.out.println(Character.isLetter('c'));
        System.out.println(Character.isLetter('5'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println(Character.isDigit('c'));
        System.out.println(Character.isDigit('5'));
    }
}
public class Test {
 
    public static void main(String args[]) {
        System.out.println(Character.isWhitespace('c'));
        System.out.println(Character.isWhitespace(' '));
        System.out.println(Character.isWhitespace('\n'));
        System.out.println(Character.isWhitespace('\t'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println( Character.isUpperCase('c'));
        System.out.println( Character.isUpperCase('C'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println( Character.isLowerCase('c'));
        System.out.println( Character.isLowerCase('C'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println(Character.toUpperCase('a'));
        System.out.println(Character.toUpperCase('A'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println(Character.toLowerCase('a'));
        System.out.println(Character.toLowerCase('A'));
    }
}
public class Test {

    public static void main(String args[]) {
        System.out.println(Character.toString('a'));
        System.out.println(Character.toString('A'));
    }
}