当一个线程进入一个对象的一个synchronized方法后，其它线程是否可进入此对象的其它方法?

分两种情况

         1)：进入此对象的非同步方法

              答案：可以

         2)：进入此对象的同步方法

             答案：不可以

第一种情况原代码

/**
 * 
 */
package thread;


/**
 * @author Administrator
 *
 */
public class TestClass {
    /**
     * @param args
     */
    public static void main(String[] args) {
        TestClass tc = new TestClass();
        Thread1 t1 = tc.new Thread1(tc);
        t1.start();
        Thread2 t2 = tc.new Thread2(tc);
        t2.start();
        
    }

    class Thread1 extends Thread{
        TestClass tc = null;
        public Thread1(TestClass tc) {
            this.tc = tc;
        }
        @Override
        public void run() {
            tc.method1();
        }
    }
    class Thread2 extends Thread{
        TestClass tc = null;
        public Thread2(TestClass tc) {
            this.tc = tc;
        }
        @Override
        public void run() {
            // TODO Auto-generated method stub
            tc.method2();
        }
    }
    
    public synchronized void method1(){
        System.out.println("method1");
        try {
            Thread.sleep(1000*10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    
    }
    public  void method2(){
        System.out.println("method2");
    }
}

第二种情况原代码

/**
 * 
 */
package thread;


/**
 * @author Administrator
 *
 */
public class TestClass {
    /**
     * @param args
     */
    public static void main(String[] args) {
        TestClass tc = new TestClass();
        Thread1 t1 = tc.new Thread1(tc);
        t1.start();
        Thread2 t2 = tc.new Thread2(tc);
        t2.start();
        
    }

    class Thread1 extends Thread{
        TestClass tc = null;
        public Thread1(TestClass tc) {
            this.tc = tc;
        }
        @Override
        public void run() {
            tc.method1();
        }
    }
    class Thread2 extends Thread{
        TestClass tc = null;
        public Thread2(TestClass tc) {
            this.tc = tc;
        }
        @Override
        public void run() {
            // TODO Auto-generated method stub
            tc.method2();
        }
    }
    
    public synchronized void method1(){
        System.out.println("method1");
        try {
            Thread.sleep(1000*10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    public synchronized void method2(){
        System.out.println("method2");
    }
}