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'));

    }

}