Java tread Multithreading (1) Implements runnable interface

Author: Ching

Original address: http://blog.csdn.net/qingdujun/article/details/39347245

This article demonstrates that tread multithreading implements the Runnable interface and simply explains why there is a way to create threads.

First, create a thread in the 2 method:

1) inherit the thread class to implement multi-threading, see my previous article: Java Tread Multithreading (0) a simple multithreaded instance;

2) The second method is to implement the Runnable interface and create a new thread.

Second, why should there be two ways to create a thread?

① main reason: It is method 1) can not meet our needs, so it produced a method 2);

② can not meet the requirements of the reason: mainly Java can only have a single inheritance, if a class student must inherit from the person class, but some content in student we have to implement multi-threading, this is not contradictory? (Because Method 1 implements multithreading, it must inherit from thread.) ), so here is the introduction of the Runnable method: implementation of the Runnable interface to achieve multi-threading effect, it is recommended to use the second method, that is, the method of this article.

A City small demo

Package THREAD.RUNABLE1.QDJ;//1. Defines the class implementation Runnable interface class RUNDEMO1 implements runnable{private int x = 0;//2. Overwrite the Run method in the Runnable interface//to store the thread code in run public void run () {while (x <=) System.out.println ("Runnable:" + (+ +)}} public class CRunableDemo1 {public static void main (string[] args) {RunDemo1 r = new RunDemo1 ()//3. Thread objects are established through the thread class and Runn The subclass object of the able interface as the parameter Thread t1 = new Thread (r); Thread t2 = new Thread (r);//4. Using start to open thread T1.start (); T2.start ();}}

Running Results display: (0-10 printed here, note: No Duplicates)

By running the results above, we'll try to compare the following code (define x as a local variable):

Package THREAD.RUNABLE1.QDJ;//1. Defines the class implementation Runnable interface class RUNDEMO1 implements runnable{//private int x = 0;//2. Overwrite the Run method in the Runnable interface//to store the thread code in run public void run () {for (int x = 0; x <= 3; ++x) System.out.println ("Runnable:" +x);} public class CRunableDemo1 {public static void main (string[] args) {RunDemo1 r = new RunDemo1 ()//3. Thread objects are established through the thread class and Runn The subclass object of the able interface as the parameter Thread t1 = new Thread (r); Thread t2 = new Thread (r);//4. Using start to open thread T1.start (); T2.start ();}}

The result of the run is shown (printed here 2 times did you find it?) ):

The comparison of two cases, in fact, also illustrates a problem:

Conclusion: Local variables have a copy within each thread.

References: Java video Bi Xiangdong presenter

Original address: http://blog.csdn.net/qingdujun/article/details/39347245

Java tread Multithreading (1) Implements runnable interface