多线程 一个线程增加变量 一个线程打印变量值

一道面试题，多线程， 一个线程增加变量，另一个打印出变量值。我的做法：

public class MultiThreadsTest {   
       
    int size = 1000;   
    private int i= 0;   
    boolean printlable = false;   
    Object lock = new Object();   
  
    Thread addI = new Thread(new Runnable(){   
        public void run(){   
            for(int j=0; j<size; j++){   
                synchronized(lock){   
                    if(printlable){   
                        try {   
                            lock.wait();   
                        } catch (InterruptedException e) {   
                            e.printStackTrace();   
                        }   
                    }   
                }   
                synchronized(lock){   
                    i++;                       
                    printlable = true;   
                    lock.notify();   
                }   
                   
            }   
        }   
    });   
       
    Thread printI = new Thread(new Runnable(){   
        public void run(){   
            for(int j=0; j<size; j++){   
                synchronized(lock){   
                    if(!printlable){   
                        try {   
                            lock.wait();   
                        } catch (InterruptedException e) {   
                            e.printStackTrace();   
                        }   
                    }   
                }   
                synchronized(lock){   
                    System.out.println(i);   
                    printlable = false;   
                    lock.notify();   
                }   
                   
                   
            }              
        }   
    });
    
    public static void main(String[] args){
    	MultiThreadsTest mt = new MultiThreadsTest();
    	mt.addI.start();
    	mt.printI.start();
    }
}