在Java应用程序中用Thread的子类创建两个线程，这两个线程分别在命令行窗口输出20句“大象”和“轿车”；主线程在命令行窗口中输出15句“主人”。 -In the Java application, the two thread is created by using Thread s sub class. The two threads are respectively output the command line window, the elephant and car t