multithreading - 为什么这会抛出 java.lang.IllegalMonitorStateException

Question

这个问题来自 Leetcode：https ://leetcode.com/problems/print-zero-even-odd/

这是我的代码：

class ZeroEvenOdd {
    private int n;
    
    State state;
    Type prevState = Type.EVEN;
    int count = 1;
    public ZeroEvenOdd(int n) {
        this.n = n;
        state = new State(Type.ZERO);
    }

    // printNumber.accept(x) outputs "x", where x is an integer.
    public void zero(IntConsumer printNumber) throws InterruptedException {
        synchronized(state){
            while(state.type != Type.ZERO){
                state.wait();
            }
            
            printNumber.accept(0);
            
            if(prevState == Type.EVEN)
                state.type = Type.ODD;
            else
                state.type = Type.EVEN;
                
        }
       state.notifyAll();

    }

    public  void even(IntConsumer printNumber) throws InterruptedException {
        synchronized(state){
            while(state.type != Type.EVEN){
                state.wait();
            }
            
            printNumber.accept(count);
            count++;
            prevState = state.type;
            state.type = Type.ZERO;

        }     
        
         state.notifyAll();

    }

    public  void odd(IntConsumer printNumber) throws InterruptedException {
        synchronized(state){
            while(state.type != Type.ODD){
                state.wait();
            }
            
            printNumber.accept(count);
            count++;
            prevState = state.type;
            state.type = Type.ZERO;
        }    
            state.notifyAll();

    }
    
    public class State{
        
        public Type type;
        
        public State(Type type){
            this.type = type;
        }
    }
    
    public enum Type {
        ZERO, ODD, EVEN
    }
}

我们需要打印01020304050

收到以下错误：Thrown exception java.lang.IllegalMonitorStateException

不知道我哪里出错了？我是多线程和并发的新手。有人可以帮忙吗？

谢谢你。