20165218 2017-2018-1 "Java Programming" Week 8 Learning Summary

Textbook learning content summary

Chapter 12 Java Multithreading Mechanisms

threads in java

A computer can only execute one thread at any given time , and the multi-threading mechanism refers to the Java virtual machine quickly switching threads so that they execute in turn
ThreadObjects of class and its subclasses represent threads
A thread's life cycle has four states : new, running, interrupted, and dead
setPriority(int grade)method to adjust thread priority

Common methods of threading

start()Only threads in the newly created state can call
run()There is no specific content, the user program needs to create a subclass of its own Thread class and override the run()method; after execution, the thread dies
sleep(int millsecond)Called to temporarily put a high-priority thread to sleep; must be try-catchused in
isAlive()The method returns when the thread is in the new and dead state, and returns falsewhen it is in the running statetrue
currentThread()Returns the thread that is using CPU resources
interrupt()Used to "wake up" sleepthe thread that called the method

thread synchronization

The method of using synchronized modification must comply with the synchronization mechanism: when a thread A uses the synchronized method, other threads must wait until thread A is finished using this method.

coordinating synchronized threads

wait()The method can interrupt the execution of the thread and temporarily give up the right to use the CPU
wait()method must notifyAll()wake up with method
wait()Methods, notify(), notifyAll()are final methods in the Object class and are not allowed to be overridden

thread union

//线程A在使用CPU资源的期间
B.join();

A interrupts immediately until thread B finishes executing

code hosting

(screenshot of the running result of the statistics.sh script)

Summary of last week's exam mistakes

wrong question 1

Connection is a class name not a method name

wrong question 2
...

"Java Programming" Week 8 Learning Summary 20165218 2017-2018-1