Multithreading in Java

Java uses thread to represent threads, and all thread objects must be instances of the thread class or its subclasses. The role of each thread is to execute a program flow (accomplish a certain task).

Java uses the thread execution body to represent this program flow.

1. Inheriting the thread class to create a threading class

Package Org.apache;public class ThreadDemo1 extends thread {private int i;/* * Overrides the Run method, which is the thread execution body * When the thread class inherits the threads class, use this immediately Can get the current thread * Call the GetName () method directly to return the name of the current thread */public void run () {for (; i<100;i++) {System.out.println (GetName () + "" + i);}} public static void Main (string[] args) {for (int i=0;i<100;i++) {System.out.println (Thread.CurrentThread (). GetName ( + "" +i), if (i==20) {//creates and starts the first thread new ThreadDemo1 (). Start ();//Create and start the second thread new ThreadDemo1 (). Start ();}}}

Execution Result:

Note: The program actually has three threads, and the main () method is the main thread, which shows the creation of two child threads.

The values of Thread-0 and Thread-1 I are discontinuous, so Thread-0 and Thread-1 cannot share instance variables of the thread class.

2. Implement the Runnable interface to create a threading class

Package Org.apache;public class ThreadDemo2 implements Runnable {private int i;//must be Runnable when implementing Thread.CurrentThread interface (). GetName () Gets the current thread, public void, run () {for (; i<100;i++) {System.out.println (Thread.CurrentThread (). GetName () + "" "+ i) ;}} public static void Main (string[] args) {for (int i=0;i<100;i++) {System.out.println (Thread.CurrentThread (). GetName ( ) + "" +i), if (i==20) {ThreadDemo2 td = New ThreadDemo2 ();//Create thread new threads (TD, "Thread 1") through the new Thread (Target,name) method. Start (); New Thread (TD, "Thread 2"). Start ();}}}

Results:

The value of I is continuous, sharing an instance variable of the same thread class (actually the target class of the thread)

Multithreading in Java