Methods for creating multithreads ---1 creating subclasses of thread class and multithreading principle

Method of creating multithreading

The first way to create multithreading ： establish Thread Subclasses of classes Java.lang.Thread class ： Is a class that describes threads , We want to implement multithreaded programs , Must inherit Thread class . Implementation steps ： 1. Create a Thread Subclasses of classes . 2. stay Thread In a subclass of class run Method , Set up thread tasks （ What does the thread do ）. 3. establish Thread Subclass object of class . 4. call Thread Methods in class start（） Method , perform run Method . void start（） Use this thread to start execution ,Java The virtual machine calls the thread's run Method . The result is two threads running concurrently , Current thread （main Threads ; Also called main thread ） And another thread （ Create a new thread , To perform its run Method ）. It's illegal to start a thread multiple times . Especially when the thread has finished executing , Can't restart again . Java The program is preemptive scheduling , Which thread has the highest priority Which one to execute first , Select one at random for the same priority . Example ：

Main method ：

result ： Two threads are preempting CPU execution time .

Multi thread random printing principle ：