How to Make Threads Run Again
Threads are the courage of multithreading. We are living in a real-world which in itself is defenseless on the web surrounded by lots of applications. Same this with the advocacy in technologies we cannot compensate with the speed for which we need to run them simultaneously for which we demand more applications to run in parallel. It is achieved by the concept of thread.
Real-life Example
Suppose you are using two tasks at a fourth dimension on the computer be it using Microsoft Word and listening to music. These two tasks are called processes. So yous outset typing in Word and at the same time music up there, this is chosen multitasking. Now you committed a fault in a Word and spell check shows exception, this means even a Discussion is a process that is broken down into sub-processes. At present if a machine is dual-core and then one process or chore is been handled past ane cadre and music is been handled by another cadre.
In the above example, we come across both multiprocessing and multithreading are somehow indirectly used to achieve multitasking. We accept achieved In this way the mechanism of dividing the tasks is called multithreading in which every process or task is chosen by a thread where a thread is responsible for when to execute, when to stop and how long to exist in a waiting country. Hence, a thread is the smallest unit of processing whereas multitasking is a process of executing multiple tasks at a time.
Multitasking is being achieved in ii ways:
- Multiprocessing: Process-based multitasking is a heavyweight process and occupies unlike accost spaces in memory. Hence, while switching from one process to some other volition require some time be it very small causing a lag while switching as registers volition be loaded in memory maps and the listing will be updated.
- Multithreading: Thread-based multitasking is a lightweight process and occupies the same accost space. Hence, while switching toll of communication will be very less.
Below is the Lifecycle of a Thread been illustrated
- New: When a thread is just created.
- Runnable: When a showtime() method is chosen over thread processed by the thread scheduler.
- Example A: Can exist a running thread
- Case B: Tin can not exist a running thread
- Running: When it hits example 1 means the scheduler has selected it to be run the thread from runnable state to run state.
- Blocked: When it hits instance 2 significant the scheduler has selected not to allow a thread to alter country from runnable to run.
- Terminated: When the run() method exists or stop() method is called over a thread.
If we exercise incorporate threads in operating systems one can perceive that the process scheduling algorithms in operating systems are strongly deep-down working on the aforementioned concept incorporating thread in Gantt charts. A few of the most popular are listed below which wraps upwardly all of them and are used practically in software evolution.
- Commencement In Offset Out
- Concluding In Outset Out
- Round Robin Scheduling
Now one Imagine the concept of Deadlock in operating systems with threads by now how the switching is getting computed over internally if one but has an overview of them.
So bar far we have understood multithreading and thread conceptually, so we can conclude out advantages of multithreading before introducing to whatever other concept or getting to programs in multithreading.
- The user is not blocked as threads are independent even if there is an issue with one thread and so but the corresponding procedure volition be stopped residue all the operations volition be computed successfully.
- Saves time every bit likewise many operations are carried over at the same time causing work to get finished as if threads are non used the just i process will be handled by the processor.
- Threads are independents though being sharing the same address space.
So nosotros have touched all chief concepts of multithreading but the question striving in the head is left. why do we demand it, where to employ it and how? At present, will discuss all iii scenarios why multithreading is needed and where it is implemented via the aid of programs in which we will exist further learning more about threads and their methods. We need multithreading in four scenarios every bit listed.
- Thread Class
- Mobile applications
- Asynchronous thread
- Web applications
- Game Evolution
Note: Past default we only take one main thread which is responsible for main thread exception as you have encountered even without having any prior knowledge of multithreading
Two Ways to Implement Multithreading
- Using Thread Class
- Using Runnable Interface
Method ane: Using Thread Class
Java provides Thread class to achieve programming invoking threads thereby some major methods of thread form are shown beneath in the tabular format with which nosotros deal often along the action performed by them.
| Methods | Activity Performed |
|---|---|
| isDaemon() | It checks whether the current thread is daemon or non |
| starting time() | It starts the execution of the thread |
| run() | It does the executable operations statements in the torso of this method over a thread |
| sleep() | Information technology is a static method that puts the thread to slumber for a sure time been passed as an argument to it |
| wait() | It sets the thread back in waiting state. |
| notify() | Information technology gives out a notification to ane thread that is in waiting country |
| notifyAll() | It gives out a notification to all the thread in the waiting state |
| setDaemon() | It set the current thread as Daemon thread |
| terminate() | It is used to cease the execution of the thread |
| resume() | It is used to resume the suspended thread. |
Pre-requisites: Bones syntax and methods to deal with threads
At present let u.s.a. come up with how to set the proper noun of the thread. By default, threads are named thread-0, thread-1, and so on. But in that location is as well a method been there that is oft used refer to every bit setName() method. Also corresponding to it at that place is a method getName() which returns the proper name of the thread exist it default or settled already by using setName() method. The syntax is as follows:
Syntax:
(a) Returning the name of the thread
public String getName() ;
(b) Changing the proper name of the thread
public void setName(Cord name);
Taking a step further, let us dive into the implementation part to learn more concepts almost multithreading. And so, there are basically two means of implementing multithreading:
Illustration: Consider if one has to multiply all elements by 2 and there are 500 elements in an array.
Examples
Java
course MyThread1 extends Thread {
public void run()
{
System.out.println( "Thread1 is running" );
}
}
class MyThread2 extends Thread {
public void run()
{
Arrangement.out.println( "Thread2 is running" );
}
}
class GFG {
public static void main(String[] args)
{
MyThread1 obj1 = new MyThread1();
MyThread2 obj2 = new MyThread2();
obj1.start();
obj2.start();
}
}
Java
class MyThread1 extends Thread {
public void run() {
System.out.println( "Thread ane is running" );
}
}
class MyThread2 extends Thread {
public void show() {
Organization.out.println( "Thread 2" );
}
}
course GFG {
public static void main(Cord[] args) {
MyThread1 obj1 = new MyThread1();
MyThread2 obj2 = new MyThread2();
obj1.starting time();
obj2.outset();
}
}
Java
course MyThread1 extends Thread {
public void run() {
System.out.println( "Thread i is running" );
}
}
class MyThread2 extends Thread {
public void testify() {
System.out.println( "Thread 2" );
}
}
class GFG {
public static void main(String[] args) {
MyThread1 obj1 = new MyThread1();
MyThread2 obj2 = new MyThread2();
obj1.kickoff();
obj2.show();
}
}
Output:
Instance one:
Thread1 is running Thread2 is running
Here we do have created our ii thread classes for each thread. In the primary method, nosotros are simply creating objects of these thread classes where objects are now threads. So in main, we telephone call thread using beginning() method over both the threads. Now start() method starts the thread and lookup for their run() method to run. Here both of our thread classes were having run() methods, then both threads are put to run state from runnable past the scheduler, and output on the console is justified.
Case 2:
Thread 1 is running
Here nosotros do take created our ii thread classes for each thread. In the primary method, we are only creating objects of these thread classes where objects are now threads. So in chief, we call thread using beginning() method over both the threads. Now showtime() method starts the thread and lookup their run() method to run. Hither simply form 1 is having the run() method to brand the thread transcend from runnable to tun state to execute whereas thread 2 is merely created but not put to run state by the scheduler as its corresponding run() method was missing. Hence, but thread 1 is called rest thread 2 is created but and is in the runnable land afterward blocked by scheduler because the corresponding run() method was missing.
Case 3:
Thread 2 Thread one is running
Method 2: Using Runnable Interface
Some other way to accomplish multithreading in java is via the Runnable interface. Hither as we have seen in the in a higher place instance in style 1 where Thread form is extended. Here Runnable interface beingness a functional interface has its own run() method. Here classes are implemented to the Runnable interface. Later on, in the main() method, Runnable reference is created for the classes that are implemented in order to make bondage between with Thread class to run our own corresponding run() methods. Farther, while creating an object of Thread form nosotros will pass these references in Thread class as its constructor allows an merely runnable object, which is passed as a parameter while creating Thread class object in a chief() method. Now lastly just likely what we did in Thread course, start() method is invoked over the runnable object who are now already linked with Thread grade objects, so the execution begins for our run() methods in instance of Runnable interface. It is shown in the program below as follows:
Example:
Java
import coffee.io.*;
import java.util.*;
class MyThread1 implements Runnable {
public void run()
{
for ( int i = 0 ; i < five ; i++) {
System.out.println( "Thread1" );
try {
Thread.sleep( k );
}
catch (Exception e) {
}
}
}
}
form MyThread2 implements Runnable {
public void run()
{
for ( int i = 0 ; i < v ; i++) {
Organisation.out.println( "Thread2" );
try {
Thread.slumber( yard );
}
catch (Exception e) {
}
}
}
}
public form GFG {
public static void main(String[] args)
{
Runnable obj1 = new MyThread1();
Runnable obj2 = new MyThread2();
Thread t1 = new Thread(obj1);
Thread t2 = new Thread(obj2);
t1.get-go();
t2.start();
}
}
Output
Thread2 Thread1 Thread2 Thread1 Thread2 Thread1 Thread2 Thread1 Thread2 Thread1
Points to remember: Whenever you lot anted to create threads, there are simply 2 ways:
- Extending the grade
- Implementing the interface which is runnable
Brand sure to create an object of threads in which you have to laissez passer the object of runnable
Special Methods of Threads
Now permit us hash out there are various methods been there for threads. Here we will be discussing out major ones in society to have a practical agreement of threads and multithreading which are sequential every bit follows:
- start() Method
- append() Method
- stop() Method
- expect() Method
- notify() Method
- notifyAll() Method
- sleep() Method
- Output Without sleep() Method
- Output with sleep() method in Serial Execution Processes (Blocking methods approach)
- Output with sleep() method in Parallel Execution Processes (Unblocking methods approach)
- bring together() Method
Note: For naive users in multithreading where threads are courage get through Plan iv to get very basics of threads, how to start, make information technology hold, or finish then only toggle to program 1 and rest as follows.
Implementation:
Java
class Shot extends Thread {
public void show() {
for ( int i = 0 ; i < 5 ; i++) {
Arrangement.out.println( "Shot" );
}
}
}
class Miss extends Thread {
public void show() {
for ( int i = 0 ; i < 5 ; i++) {
Organization.out.println( "Miss" );
}
}
}
public class GFG {
public static void master(String[] args) {
Shot obj1 = new Shot();
Miss obj2 = new Miss();
obj1.bear witness();
obj2.prove();
}
}
Coffee
class Shot extends Thread {
public void show()
{
for ( int i = 0 ; i < v ; i++) {
System.out.println( "Shot" );
effort {
Thread.sleep( one thousand );
}
take hold of (Exception eastward) {
}
}
}
}
form Miss extends Thread {
public void testify()
{
for ( int i = 0 ; i < five ; i++) {
Organization.out.println( "Miss" );
endeavour {
Thread.sleep( thousand );
}
catch (Exception e) {
}
}
}
}
public form GFG {
public static void master(Cord[] args)
{
Shot obj1 = new Shot();
Miss obj2 = new Miss();
obj1.kickoff();
obj2.start();
obj1.show();
obj2.show();
}
}
Java
class Shot extends Thread {
public void run()
{
for ( int i = 0 ; i < 5 ; i++) {
Arrangement.out.println( "Shot" );
try {
Thread.sleep( k );
}
catch (Exception e) {
}
}
}
}
class Miss extends Thread {
public void run()
{
for ( int i = 0 ; i < 5 ; i++) {
System.out.println( "Miss" );
try {
Thread.sleep( 1000 );
}
catch (Exception eastward) {
}
}
}
}
public class GFG {
public static void principal(String[] args)
{
Shot obj1 = new Shot();
Miss obj2 = new Miss();
obj1.beginning();
obj2.commencement();
}
}
Output:
Example 1:
Shot Shot Shot Shot Shot Miss Miss Miss Miss Miss
Case 2: Video output
Shot Shot Shot Shot Shot Miss Miss Miss Miss Miss
Case 3: Video output
Shot Miss Shot Miss Shot Miss Shot Miss Shot Miss
Notation: There is no priority been set for threads for which as per the club of execution of threads outputs volition vary then do remember this drawback of multithreading of dissimilar outputs leading to information inconsistency issues which nosotros will be discussing in-depth in the later office nether synchronization in threads.
Priorities in Threads
Priorities in threads is a concept where each thread is having a priority which in layman's language one can say every object is having priority hither which is represented by numbers ranging from 1 to 10.
- The default priority is set to 5 equally excepted.
- Minimum priority is set to 0.
- Maximum priority is set to 10.
Here three constants are defined in it namely equally follows:
- public static int NORM_PRIORITY
- public static int MIN_PRIORITY
- public static int MAX_PRIORITY
Let u.s. talk over it with an example to become how internally the work is getting executed. Hither we will exist using the knowledge gathered higher up as follows:
- We volition use currentThread() method to become the name of the current thread. User tin also use setName() method if he/she wants to make names of thread as per choice for understanding purposes.
- getName() method will be used to get the name of the thread.
Coffee
import java.io.*;
import java.util.*;
form MyThread extends Thread {
public void run()
{
System.out.println( "Running Thread : "
+ currentThread().getName());
System.out.println( "Running Thread Priority : "
+ currentThread().getPriority());
}
}
class GFG {
public static void main(String[] args)
{
MyThread t1 = new MyThread();
MyThread t2 = new MyThread();
t1.starting time();
t2.start();
}
}
Java
import coffee.io.*;
import coffee.util.*;
course MyThread extends Thread {
public void run()
{
System.out.println( "Running Thread : "
+ currentThread().getName());
Organisation.out.println( "Running Thread Priority : "
+ currentThread().getPriority());
}
}
class GFG {
public static void main(String[] args)
{
MyThread t1 = new MyThread();
MyThread t2 = new MyThread();
t1.setPriority(Thread.NORM_PRIORITY);
t2.setPriority(Thread.NORM_PRIORITY);
t1.outset();
t2.start();
}
}
Java
import java.io.*;
import java.util.*;
class MyThread extends Thread {
public void run()
{
Organisation.out.println( "Running Thread : "
+ currentThread().getName());
Organization.out.println( "Running Thread Priority : "
+ currentThread().getPriority());
}
}
class GFG {
public static void main(String[] args)
{
MyThread t1 = new MyThread();
MyThread t2 = new MyThread();
t1.setPriority(Thread.MIN_PRIORITY);
t2.setPriority(Thread.MIN_PRIORITY);
t1.start();
t2.start();
}
}
Java
import java.io.*;
import java.util.*;
grade MyThread extends Thread {
public void run()
{
Organisation.out.println( "Running Thread : "
+ currentThread().getName());
Arrangement.out.println( "Running Thread Priority : "
+ currentThread().getPriority());
}
}
course GFG {
public static void primary(String[] args)
{
MyThread t1 = new MyThread();
MyThread t2 = new MyThread();
t1.setPriority(Thread.MAX_PRIORITY);
t2.setPriority(Thread.MAX_PRIORITY);
t1.get-go();
t2.start();
}
}
Output:
Example 1: Default Priority
Running Thread : Thread-0 Running Thread : Thread-1 Running Thread Priority : v Running Thread Priority : 5
Case 2: NORM_PRIORITY
Running Thread : Thread-0 Running Thread : Thread-1 Running Thread Priority : 5 Running Thread Priority : five
Case iii: MIN_PRIORITY
Running Thread : Thread-0 Running Thread : Thread-ane Running Thread Priority : one Running Thread Priority : 1
Instance 4: MAX_PRIORITY
Running Thread : Thread-1 Running Thread : Thread-0 Running Thread Priority : 10 Running Thread Priority : ten
Output Explanation:
If nosotros look carefully we do see the outputs for cases 1 and 2 are equivalent. This signifies that when the user is non even enlightened of the priority threads still NORM_PRIORITY is showcasing the aforementioned result up to what default priority is. It is because the default priority of running thread as soon as the respective starting time() method is called is executed as per setting priorities for all the thread to 5 which is equivalent to the priority of NORM case. This is because both the outputs are equivalent to each other. While in instance 3 priority is set to a minimum on a scale of one to ten and then practice the same in case 4 where priority is assigned to x on the aforementioned scale.
Hence, all the outputs in terms of priorities are justified. Now let united states of america move ahead onto an important aspect of priority threading been incorporated in daily life is Daemon thread
Daemon thread is basically a service provider thread that provides services to the user thread. The scope for this thread start() or be it terminate() is completely dependent on the user's thread as information technology supports in the backend for user threads being getting run. As soon as the user thread is terminated daemon thread is likewise terminated at the same fourth dimension as being the service provider thread.
Hence, the characteristics of the Daemon thread are as follows:
- It is only the service provider thread non responsible for interpretation in user threads.
- So, it is a depression-priority thread.
- It is a dependent thread as information technology has no existence on its own.
- JVM terminates the thread as soon as user threads are terminated and come back into play every bit the user's thread starts.
- Aye, you judge the most popular example is garbage collector in java. Some other examples do include 'finalizer'.
Exceptions: IllegalArgumentException every bit return blazon while setting a Daemon thread is boolean and so do utilize carefully.
Note: To get rid of the exception users thread should only beginning afterward setting it to daemon thread. The other way of starting prior setting it to daemon will not work as it will pop-out IllegalArgumentException
As discussed above in the Thread class two most widely used method is equally follows:
| Daemon Thread Methods | Action Performed |
|---|---|
| isDaemon() | It checks whether the current thread is a daemon thread or non |
| setDaemon() | Information technology fix the thread to be marked as daemon thread |
Permit united states talk over the implementation of the Daemon thread before jumping onto the garbage collector.
Java
import java.io.*;
import java.util.*;
form CheckingMyDaemonThread extends Thread {
public void run()
{
if (Thread.currentThread().isDaemon()) {
System.out.println(
"I am daemon thread and I am working" );
}
else {
Arrangement.out.println(
"I am user thread and I am working" );
}
}
}
grade GFG {
public static void main(Cord[] args)
{
CheckingMyDaemonThread t1
= new CheckingMyDaemonThread();
CheckingMyDaemonThread t2
= new CheckingMyDaemonThread();
CheckingMyDaemonThread t3
= new CheckingMyDaemonThread();
t2.setDaemon( true );
t1.offset();
t2.start();
t3.start();
}
}
Coffee
import java.io.*;
import coffee.util.*;
form CheckingMyDaemonThread extends Thread {
public void run()
{
if (Thread.currentThread().isDaemon()) {
Arrangement.out.println(
"I am daemon thread and I am working" );
}
else {
System.out.println(
"I am user thread and I am working" );
}
}
}
grade GFG {
public static void principal(String[] args)
{
CheckingMyDaemonThread t1
= new CheckingMyDaemonThread();
CheckingMyDaemonThread t2
= new CheckingMyDaemonThread();
CheckingMyDaemonThread t3
= new CheckingMyDaemonThread();
t1.kickoff();
t2.start();
t3.showtime();
t2.setDaemon( truthful );
}
}
Some other way to achieve the aforementioned is through Thread Grouping in which every bit the name suggests multiple threads are treated as a single object and later on on all the operations are carried on over this object itself aiding in providing a substitute for the Thread Pool.
Note:
While implementing ThreadGroup practice notation that ThreadGroup is a role of ' java.lang.ThreadGroup' course not a part of Thread class in java so do peek out constructors and methods of ThreadGroup class before moving alee keeping a bank check over deprecated methods in his class and then as not to confront any ambiguity farther.
Hither principal() method in itself is a thread because of which yous do come across Exception in main() while running the program because of which arrangement.chief thread exception is thrown sometimes while execution of the program.
Synchronization
It is the machinery that bounds the access of multiple threads to share a common resource hence is suggested to be useful where but one thread at a time is granted the access to run over.
It is implemented in the plan past using 'synchronized' keyword.
Now let's finally discuss some advantages and disadvantages of synchronization before implementing the same. For more than depth in synchronization, one tin can too acquire object level lock and class level lock and do notice the differences between ii to get a off-white understanding of the same before implementing the same.
Why synchronization is required?
- Data inconsistency issues are the main issue where multiple threads are accessing the common memory which sometimes results in faults in order to avert that a thread is overlooked by some other thread if information technology fails out.
- Data integrity
- To piece of work with a common shared resource which is very essential in the real globe such as in cyberbanking systems.
Note: Exercise not become for synchronized keyword unless information technology is most needed, remember this as there is no priority setup for threads, so if the main thread runs before or afterwards other thread the output of the program would be different.
The biggest advantage of synchronization is the increase in idiotic resistance as 1 can non choose arbitrarily an object to lock on as a result string literal tin not be locked or be the content. Hence, these bad practices are not possible to perform on synchronized method cake.
Equally we accept seen humongous advantages and go to know how of import information technology is but at that place comes disadvantage with it.
Disadvantage: Functioning issues will arise every bit during the execution of one thread all the other threads are put to a blocking state and do note they are non in waiting land. This causes a performance drop if the fourth dimension taken for one thread is also long.
As perceived from the image in which we are getting that count variable existence shared resources is updating randomly. Information technology is because of multithreading for which this concept becomes a necessity.
- Example 1: If 'main thread' executes first and so count will be incremented followed by a 'thread T' in synchronization
- Instance ii: If 'thread T' executes first and then count will not increase followed by 'main thread' in synchronization
Implementation: Let us take a sample plan to observe this 0 one count conflict
Case:
Coffee
import coffee.io.*;
import coffee.util.*;
class MyThread extends Thread {
int count = 0 ;
void increment() { count++; }
public void run()
{
increment();
Organization.out.println( "Count : " + count);
}
}
public class GFG {
public static void main(Cord[] args)
{
MyThread t1 = new MyThread();
t1.kickoff();
}
}
Output:
Output Explanation:
Here the count is incremented to i meaning 'main thread' has executed prior to 'created thread'. We have run it many times and compiled and run one time again wherein all cases hither primary thread is executing faster than created thread merely exercise recollect output may vary. Our created thread tin execute prior to 'master thread' leading to 'Count : 0' as an output on the console.
Now another topic that arises in dealing with synchronization in threads is Thread safety in java synchronization is the new concept that arises out in synchronization so let us discuss information technology because
- A real-life scenario followed by
- Pictorial representation as an illustration followed past
- Technically clarification and implementation
Existent-life Scenario
Suppose a person is withdrawing some corporeality of money from the bank and at the same time the ATM card registered with the same business relationship number is carrying on withdrawal operation past some other user. Now suppose if withdrawing some amount of money from net cyberbanking makes funds in account lesser than the corporeality which needed to exist withdrawal or the other way. This makes the bank unsafe as more funds are debited from the account than was actually present in the account making the bank very dangerous and is not seen in daily life. So what banks exercise is that they only permit ane transaction at a time. Once it is over then another is permitted.
Illustration:
Interpreting the same engineering every bit in that location are two different processes going on which object in instance of parallel execution is over headed by threads. Now possessing such traits over threads such that they should look subsequently for earlier execution or in simpler words making them synchronized. This machinery is referred to as Thread Condom with the utilise of the keyword 'synchronized' before the common shared method/function to be performed parallel.
Technical Description:
As we know Coffee has a feature, Multithreading, which is a process of running multiple threads simultaneously. When multiple threads are working on the same data, and the value of our data is irresolute, that scenario is not thread-rubber, and we will get inconsistent results. When a thread is already working on an object and preventing another thread from working on the same object, this process is called Thread-Safety. Now there are several ways to achieve thread-safety in our program namely as follows:
- Using Synchronization
- Using Volatile Keyword
- Using Diminutive Variable
- Using Terminal Keyword
Conclusion: Hence, if we are accessing one thread at a time then we can say thread-safe program and if multiple threads are getting accessed and so the program is said to be thread-unsafe that is one resources at a time can not be shared by multiple threads at a time.
Implementation:
- Coffee Program to illustrate Incomplete Thread Iterations returning counter value to Zero irrespective of iteration bound
- Java Program to Illustrate Complete Thread Iterations illustrating join() Method
- Java Plan to Illustrate thread-unsafe or not-synchronizing programs every bit of incomplete iterations
- Coffee Plan to Illustrate Thread Rubber And synchronized Programs equally of Complete iterations using 'synchronized' Keyword.
Examples
Java
import java.io.*;
class TickTock {
int count;
public void increase()
{
count++;
}
}
class GFG {
public static void main(String[] args) throws Exception
{
TickTock tt = new TickTock();
Thread t1 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 10000 ; i++) {
tt.increment();
}
}
});
t1.outset();
System.out.println( "Count : " + tt.count);
}
}
Java
import java.io.*;
course TickTock {
int count;
public void increment()
{
count++;
}
}
class GFG {
public static void principal(Cord[] args) throws Exception
{
TickTock tt = new TickTock();
Thread t1 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 1000 ; i++) {
tt.increment();
}
}
});
t1.start();
t1.bring together();
System.out.println( "Count : " + tt.count);
}
}
Coffee
import java.io.*;
class TickTock {
int count;
public void increment()
{
count++;
}
}
course GFG {
public static void main(String[] args) throws Exception
{
TickTock tt = new TickTock();
Thread t1 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 100000 ; i++) {
tt.increment();
}
}
});
Thread t2 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 100000 ; i++) {
tt.increment();
}
}
});
t1.start();
t2.first();
t1.join();
t2.bring together();
System.out.println( "Count : " + tt.count);
}
}
Java
import java.io.*;
class TickTock {
int count;
public synchronized void increase()
{
count++;
}
}
class GFG {
public static void master(Cord[] args) throws Exception
{
TickTock tt = new TickTock();
Thread t1 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 100000 ; i++) {
tt.increment();
}
}
});
Thread t2 = new Thread( new Runnable() {
public void run()
{
for ( int i = 0 ; i < 100000 ; i++) {
tt.increase();
}
}
});
t1.start();
t2.start();
t1.bring together();
t2.join();
System.out.println( "Count : " + tt.count);
}
}
Output:
Case ane
Count : 0
Instance 2
Count : 10000
Case 3
Count : 151138
Case iv
Count : 200000
Output Explanation:
In case 1 we can see that count is zero equally initialized. Now nosotros have ii threads main thread and the thread t1. Then there are 2 threads so now what happens sometimes instance is shared amongst both of the threads.
In case 1 both are accessing the count variable where nosotros are directly trying to admission thread via thread t1.count which volition throw out 0 ever as nosotros need to call it with the assistance of object to perform the execution.
Now we have understood the working of synchronization is a thread that is nothing but referred to every bit a term Concurrency in java which in layman language is executing multiple tasks. Let usa depict concurrency in threads with the help of a pictorial illustration.
Consider the task of multiplying an array of elements by a multiplier of 2. Now if nosotros outset multiplying every element randomly wise it volition accept a serious amount of time equally every time the chemical element volition be searched over and computer. Past far nosotros have studied multithreading above in which we have ended to a single line that thread is the backbone of multithreading. And then incorporating threads in the in a higher place situation as the machine is quad-core we hither accept iv threads for every core where we split up the in a higher place computing sample prepare to (1/4)thursday resulting out in 4x faster computing. If in the in a higher place scenario it had taken 4 seconds and then at present it will take one second only. This mechanism of parallel running threads in society to attain faster and lag-free computations is known as concurrency.
Note: Go for multithreading e'er for concurrent execution and if non using this concept go for sequential execution despite having bigger chunks of lawmaking equally safety to our code is the primary issue.
Source: https://www.geeksforgeeks.org/java-multithreading-tutorial/
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