Java threads (1)

Java threads (1)

1. Process and thread

Multi-process:

Multiple tasks (programs) can be run in the operating system at the same time)

Multithreading:

Multiple sequential streams (at the same time) are executed in the same application.

2. multi-threaded program running mode

3. Define the thread method

Method 1:

Defines a Thread class, which inherits the class Thread and overwrites the method run (). The method run () is called the Thread body;

Because Java only supports single inheritance, classes defined using this method cannot inherit other classes.

Class FirstThread extends Thread {public void run () {for (int I = 0; I <100; I ++) {System. out. println ("FirstThread -->" + I );}}}

Note: This program has three threads.
1. The main function is a thread.
2. the ft thread object is the second thread after startup
3. Garbage collection mechanism thread

Class Test {public static void main (String args []) {// the object that generates the Thread class FirstThread ft = new FirstThread (); // start the thread ft. start ();}}

Test. Add a for loop to the Test class.

Class Test {public static void main (String args []) {// the object that generates the Thread class FirstThread ft = new FirstThread (); // start the thread (start () is required ()) ft. start (); for (int I = 0; I <100; I ++) {System. out. println ("main -->" + I );}}}

After running, two loops are found to run alternately, indicating that the two loops are in different threads.