Java 多线程 简单实例 （Thread）

package second;

public class A extends Thread {
public void run(){
for(int i = 1;i <= 10 ; i++){
for(int y=1;y<=i;y++){
System.out.print("*");
}
System.out.println();
}
}
public static void main(String args[]){
A a1 = new A();
A a2 = new A();
A a3 = new A();
a1.start();
a2.start();
a3.start();
}
}