Java multithreaded Programming (iii) Priority, synchronization, and deadlock of threads

Priority of the thread:

The priority of the thread is divided into three types, namely:

1-min_priority

10-max_priority

5-norm_priority

If nothing is set the default value is 5

The priority of a thread can affect the order in which threads are executed, and of course this refers to a possible impact that does not necessarily affect it. In the default state (for example, the main thread) its default value is 5

Specific Code Demo:

Package Com.yeqc.thread;class ThRun implements runnable{@Overridepublic void Run () {for (int i=0; i<5; i++) {try {thread . Sleep (1000); System.out.println (Thread.CurrentThread (). GetName () + ":" +i); catch (Interruptedexception e) {e.printstacktrace ();}}}} public class ThreadDemo03 {public static void main (string[] args) {thread T1 = new Thread (new ThRun (), "A"); Thread t2 = new Thread (new ThRun (), "B"); thread t3 = new Thread (new ThRun (), "C"), t1.setpriority (thread.min_priority); t2.setpriority (thread.norm_priority); T3.setpriority (thread.max_priority); T1.start (); T2.start (); T3.start ();}}

Operation Result:

C:0a:0b:0c:1b:1a:1c:2a:2b:2c:3a:3b:3c:4b:4a:4

Sync and Deadlock:

1. Synchronizing code blocks

When you add the "synchronized" keyword to a code block, this code block is called a synchronous code block

2. Synchronous code block format:

Sychronized (Synchronization object) {block of code that needs to be synchronized; }

3. Synchronization method

In addition to the code block can be synchronized, the method can be synchronized

4. Method Synchronization Format:

sychronized void Method Name () {}

Specific Code Demo:

1. Synchronous code block mode:

Package Com.yeqc.thread;class Mythreaddemo implements runnable{private int ticket = 5, @Overridepublic void Run () {for (int i = 0; I < 10; i++) {synchronized (this) {if (ticket>0) {try {Thread.Sleep],} catch (Interruptedexception e) {e.printstacktrace ( );} System.out.println ("Ticket:" +ticket--);}}}} public class ThreadDemo04 {public static void main (string[] args) {Mythreaddemo m = new Mythreaddemo (); thread T1 = new Thread (m); Thread t2 = new Thread (m); thread t3 = new Thread (m); T1.start (); T2.start (); T3.start ();}}

Operation Result:

Ticket: 5 Tickets: 4 Tickets: 3 Tickets: 2 Tickets: 1

2. Synchronization method

Package Com.yeqc.thread;class Mythreaddemo implements runnable{private int ticket = 5, @Overridepublic void Run () {for (int i = 0; I < 10; i++) {tell ();}} Public synchronized void Tell () {if (ticket>0) {try {Thread.Sleep ($)} catch (Interruptedexception e) { E.printstacktrace ();} System.out.println ("Ticket:" +ticket--);}} public class ThreadDemo04 {public static void main (string[] args) {Mythreaddemo m = new Mythreaddemo (); thread T1 = new Thread (m); Thread t2 = new Thread (m); thread t3 = new Thread (m); T1.start (); T2.start (); T3.start ();}}

Operation Result:

Ticket: 5 Tickets: 4 Tickets: 3 Tickets: 2 Tickets: 1

/**

* Deadlock: Student Job search (hi-Tech)

* Business requires you to have work experience (experience)

*/

Java multithreaded Programming (iii) Priority, synchronization, and deadlock of threads