package xiancheng;

public class Testsyn implements Runnable(){//为什么实现一个接口他还报错呀
    Timer timer = new Timer();//这个地方它显示的是分号错了
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Testsyn t = new Testsyn();
        Thread t1 = new Thread(t);
        Thread t2 = new Thread(t);
                t1.setName("t1");
                t2.setName("t2");
                t1.start();
                t2.start();
    }
    @Override
        public void run() {
            // TODO Auto-generated method stub
        timer.add(Thread.currentThread().getName());
            
        }
}
class Timer{
private static int num = 0;
public void add(String name){
    num++;
    try{
        Thread.sleep(1);
    }catch(InterruptedException e){
        System.out.println(name +"是第"+"num"+"个访问者");
        
    }
}
   
}

语法错误

你这是写一个进程，你见过在进程中写main方法的嘛？？？，写一个测试类，来掉用main方法，main方法也是一个进程，进程中调用进程？？？

你的Runnable后面为什么要加一个括号？？？你看可以解决你的问题吗？

public class Testsyn implements Runnable{//为什么实现一个接口他还报错呀
    Timer timer = new Timer();//这个地方它显示的是分号错了
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Testsyn t = new Testsyn();
        Thread t1 = new Thread(t);
        Thread t2 = new Thread(t);
                t1.setName("t1");
                t2.setName("t2");
                t1.start();
                t2.start();
    }
        public void run() {
            // TODO Auto-generated method stub
        timer.add(Thread.currentThread().getName());
            
        }
}

这样编译就没有问题了
至于实现功能，你在看看