1. 两个线程分别打印26个英文字母的元音（a,e,i,o,u）和辅音（其他）,按字母序输出

方法一：使用wait 和 notify 实现

public class WordsAlternant {

    public static String[] letters = {
            "a", "b", "c", "d", "e", "f", "g", "h", "i",
            "j", "k", "l", "m", "n", "o", "p", "q", "r",
            "s", "t", "u", "v", "w", "x", "y", "z"};

    static boolean isYuan(String s) {
        switch (s) {
            case "a":
                return true;
            case "e":
                return true;
            case "i":
                return true;
            case "o":
                return true;
            case "u":
                return true;
        }
        return false;
    }

    public static volatile int index = 0;

    public static void main(String[] args) {
        Object o = new Object();
        new Thread(new Yuan(o)).start();
        new Thread(new Fu(o)).start();

    }

    public static class Yuan implements Runnable {
        Object o;
        public Yuan(Object o) {
            this.o = o;
        }

        @Override
        public void run() {
            synchronized(o) {
                while (index <= 25) {
                    if (isYuan(letters[index])) {
                        System.out.println("元音线程" + letters[index]);
                        index++;
                    } else {
                        try {
                            notifyAll();
                            wait();
                        } catch (Exception e) {
                            //e.printStackTrace();
                        }
                    }

                }
            }
        }
    }

    public static class Fu implements Runnable {

        Object o;
        public Fu(Object o) {
            this.o = o;
        }


        @Override
        public void run() {
            while (index <= 25) {
                if (!isYuan(letters[index])) {
                    System.out.println("辅音线程" + letters[index]);
                    index++;
                } else {
                    try {
                        notifyAll();
                        wait();
                    } catch (Exception e) {
                        //e.printStackTrace();
                    }
                }

            }
        }
    }

}