When we start a thread by applying start() method on it ,how does it knows that to execute run()method?
Why do we need start() method in Thread class? In Java API
description for Thread class is written : "Java Virtual Machine calls
the run method of this thread..".
Couldn't we call method run() ourselves, without doing double call: first we call start() method which calls run() method? What is a meaning to do things such complicate?
There is some very small but important difference between using start() and run() methods. Look at two examples below:
Example one:
Code:
Thread one = new Thread();
Thread two = new Thread();
one.run();
two.run();
Example two:
Code:
Thread one = new Thread();
Thread two = new Thread();
one.start();
two.start();
The result of running examples will be different.
In Example one the threads will run sequentially: first, thread number one runs, when it exits the thread number two starts.
In Example two both threads start and run simultaneously.
Conclusion: the start() method call run() method asynchronously (does not wait for any result, just fire up an action), while we run run() method synchronously - we wait when it quits and only then we can run the next line of our code.
