Java中线程的同步方法（线程必须是同一个同步方法）

package cn.com.secn.thead;class Printer{synchronized void printChar(String ch){for (int i = 1; i <= 10; i++){System.out.print(ch);}}}class MyThead extends Thread{private String ch;private Printer printer;public MyThead(String ch, Printer printer){this.ch = ch;this.printer = printer;}public void run(){for (int i = 1; i <= 5; i++){printer.printChar(ch);System.out.println();}}}public class TheadMain{public static void main(String[] args){Printer printer = new Printer();MyThead thread1 = new MyThead("A",printer);MyThead thread2 = new MyThead("B",printer);MyThead thread3 = new MyThead("C",printer);thread1.start();thread2.start();thread3.start();}}