使用2个线程计算2至50000之间的素数。分别使用Thread类、Runnable接口和线程组3种方法编写程序。-Use two threads to calculate the prime numbers between 2-50000. , Respectively, three kinds of ways to write programs using the Thread class, Runnable interface, and thread group.Use two threads to calculate the prime numbers between 2-50000. , Respectively, three kinds of ways to write programs using the Thread class, Runnable interface, and thread group.