public class Test {

    static class Mother extends Thread{
        /** 盐的用量 */
        final int SaltUseage = 40;
        volatile boolean cooking = true;
        Home home;
        public void run(){
            try {
                while(cooking){
                    Salt salt = home.salt;
                    if(salt.value<SaltUseage){
                        home.son.buySalt();
                        waiting();
                    }
                    System.out.println("[妈妈]盐  ==>> 当前量："+salt.value+" 用去量:"+SaltUseage+" 剩余量："+(salt.value-SaltUseage));
                    salt.value -= SaltUseage;
                    otherThings();
                }
            } catch (Exception e) {
                cooking = false;
            }
        }
        private void otherThings() {
            try {
                sleep(1000);
            } catch (Exception e) {
                cooking = false;
            }
        }
        private synchronized void waiting() throws InterruptedException {
            System.out.println("[妈妈]盐  ==>> 当前量："+home.salt.value+"  等待儿子去买盐。");
            home.mother.wait();
        }
        private synchronized void notice(){
            home.mother.notify();
        }
    }
    static class Son extends Thread{
        /** 盐的购买量 */
        final int SaltPurchases = 60;
        volatile boolean free = true;
        Home home;
        public void run(){
            try {
                while(free){
                    waiting();
                    sleep(2000);
                    System.out.println("[儿子]盐  ==>> 当前量："+home.salt.value+" 购买量:"+SaltPurchases+" 剩余量："+(home.salt.value+SaltPurchases));
                    home.salt.value += SaltPurchases;
                    notice();
                }
            } catch (Exception e) {
                free = false;
            }
        }
        public synchronized void buySalt(){
            notify();
        }
        private void notice() {
            System.out.println("[儿子]盐  ==>> 当前量："+home.salt.value+" 告知妈妈盐已买到。");
            home.mother.notice();
        }
        private synchronized void waiting() throws InterruptedException {
            System.out.println("[儿子]盐  ==>> 当前量："+home.salt.value+" 等待下次购买。");
            wait();
        }
    }
    static class Salt{
        int value = 90;
    }
    static class Home{
        Mother mother = new Mother();
        Son son = new Son();
        Salt salt = new Salt();
        public Home(){
            mother.home = this;
            son.home = this;
        }
        public void startCooking(){
            mother.start();
            son.start();
        }
        public void stopCooking(){
            mother.cooking=false;
            son.free=false;
            mother.interrupt();
            son.interrupt();
        }
    }
    
    /**
     * 测试用例
     */
    public static void main(String[] args) throws Exception {
        Home home = new Home();
        home.startCooking();
        Thread.sleep(15000);
        home.stopCooking();
    }

}

------解决方案--------------------

写着玩了一下
Java code


public class Mouther extends Thread{
    private Time t;
    public Mouther(Time t){
        this.t=t;
    }
    public void run(){
    
        synchronized (t) {
            System.out.println("做饭..");
            if(t.isHaveSalt()==false){
                try {
                    t.wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println("有盐做饭了");
                System.exit(1);
            }
    }
}
}

public class Son extends Thread{
    private Time t;
    public Son(Time t){
        this.t=t;
    }
    public void run(){
        
        synchronized (t) {
            System.out.println("sonrun");
            if(t.isHaveSalt()==false){
                System.out.println("买盐");
                for(int i=this.t.getTime();i>=0;i--){
                    System.out.println("时间:"+i);
                }
                System.out.println(t.getTime());
                System.out.println("买完.....");
                t.notifyAll();
            }
        }
    }
    public static void main(String[] args) {
    
        Time t= new Time();
        t.setTime(10000);
        t.setHaveSalt(false);
        Son s = new Son(t);
        Mouther m = new Mouther(t);
        m.start();
        s.start();
        
    }
}


public class Time {
    private int time;
    
    private boolean haveSalt;
    public boolean isHaveSalt() {
        return haveSalt;
    }

    public void setHaveSalt(boolean haveSalt) {
        this.haveSalt = haveSalt;
    }

    public int getTime() {
        return time;
    }

    public void setTime(int time) {
        this.time = time;
    }
}