Are you keen on grasping the idea of “multithreading in Java”? Ever pondered the techniques of multithreading in Java? This article will delve into various methods accompanied by code examples to simplify your learning process.
Summary of the Article:
In this article, we will discuss all the important points related to multithreading in Java and how you can implement this technique with the help of an example program.
Multithreading refers to the ability of an operating system or an application to allow multiple users without making copies of the program being executed.
This process makes CPU utilization efficient by allowing multiple requests at once. Each request is associated with threads (like user threads and daemon threads) with a unique identity.
In Java, these multiple threads are lightweight parts of a program and use a shared memory area.
We will see the various thread methods that can be used in Java to help with the operations using threads.
What Is Multithreading In Java? Read Below
In the Java programming language, multithreading is the process by which applications enable various users to perform a particular operation at the same time. From web servers to media players, you may have used many multithreaded applications daily.
Understanding Java’s core data types can be crucial to effectively utilize multithreading, especially when managing shared resources.
To perform multithreading, the Java concurrency utilities offer us efficient resources like synchronized blocks, thread pools, thread safety mechanisms, and more. In this article, we will get into details of the process and see what methods we are provided with to use this concept.
Some Real-World Applications Of Multithreading In Java
Multithreading is a vital concept in programming and software development. This concept is used in a lot of domains. Let us discuss some real-life examples and applications of Java Multithreading!
Web servers: Web applications these days get a lot of requests at the same time. So, how do servers handle this? Here is when the multithreading concept works. Every connection or request is assigned a new thread for processing so that the server can handle multiple requests at one time.
Image processing: Many image processing applications use multithreading to process and refine different parts of the images concurrently. Thus, the performance of these applications is better than the ones that use one thread for sequential image processing.
Gaming applications: Ever wondered how you can control different things in GTA? Gaming applications use multiple threads to process tasks and controls like cars, motorbikes, player controls, and more.
Word processing applications: Multithreading is also used by word processing programs like MS Word or Google Docs. How? Well, you may have encountered several grammatical errors while drafting an essay or a research paper.
Similar to assignment operators in Python, understanding how shared resources are allocated in Java is key to effective multithreading.
If you want to know more about the real time use case of multithreading then you should read our article on Payroll management systems that often involve multi-threaded transaction processing.
What Are Single Threads And Multi Threads In Java?
Threads are the lightweight sub-processes of the program and are a part of the thread class. This is like the program inside of a program. Thread is particularly used when during the program, some other tasks need to be executed or performed.
There are two types of thread-
Single thread
Multi-thread
Single threads are threads that are used only once inside the program. There is very little use of this concept as it can’t fulfill all the necessities. It can be further divided into two parts. One is a user thread & the other is a daemon thread that is used for application cleaning.
User thread: These are high-priority threads that are created by the application. They are used to perform specific tasks.
Daemon thread: Daemon threads are low-priority threads that are created by the JVM. They run in the background and support user threads.
public class Main{
public static void main(String[] args) {
System.out.println("Single Thread");}} // Only One Thread
In the above-given program, the execution of a thread can be seen by using system.out.println() when we print the output. In this, the tasks are executed sequentially.
In this article, we will learn how to multithread in Java. In the multithreading concept, several threads can be implemented with each other. And each of them will work in a completely good manner. Multithreading in Java helps a lot in animation & gaming purposes.
People often get confused between multithreading and multitasking. While multi-tasking basically means executing multiple tasks simultaneously, multithreading, on the other hand, divides a process into multiple threads that can run parallel.
// Example Of Multiple Threads
public class Zap implements Runnable{
public static void main(String[] args) {
Thread T1 = new Thread("One1"); // Declaration Of One Thread
Thread T2 = new Thread("One2"); // Declaration Of Second Thread
T1.start(); // Starting First Thread
T2.start(); // Starting Second Thread
System.out.println(T1.getName());
System.out.println(T2.getName());}
@Override
public void run() {}} // Overriding The Function
In the above example program, we see that the class Zap implements a runnable interface that helps us to execute the instance of this class as threads. Also, we can see two threads (Thread T1 and Thread T2) where each represents a thread object. Each thread is named ‘One1’ and ‘One2’ respectively.
Now, the start() thread method can be used to initialize their execution, the run method is invoked and we can print the outputs using the system.out.println() method. Each thread performs its task in isolation from the other. The void run() method is overridden.
What Are Some Terminologies Associated With Thread Object?
While studying multithreading in Java in detail, you will also come across certain terms that make up the basic concepts of Multithreading. Therefore, it is essential to have some idea about what these terms are and how they play a pivotal role in the Java multithreading programming concept.
Let’s get to know about some of the terms associated with Java Multithreading. Have a look at these below!
Thread class: This class is used to extend thread objects. It includes various methods and constructors for performing thread operations.
Thread local variables: The thread-local variables are those variables that have a local scope for each thread. They store data required for a specific thread and allow scalability.
Thread group: In Java, thread creation can occur in the form of groups. A thread group comprises a set of threads that can be managed collectively with a single function call.
Thread pool: Thread pools are effective as they allow us to reuse previously created threads called worker threads instead of creating a new thread to carry out current tasks and user requests. This also helps in saving time and managing resources.
Thread scheduler: True to its name, a thread scheduler in Java decides the currently running thread and which thread will run after the current thread. A thread scheduler can only schedule a thread if it is in the runnable state.
Thread priorities: Every thread in Java has a priority represented from 1-10. The thread scheduler arranges each thread in the order of their thread priorities as the resources are being shared.
Also read, our article on Comparable Vs Comparator. This article explains sorting & comparison, which can be optimized with multithreading.
What Are The Methods For Multithreading In Java? Get To Know
Let us now learn what is thread creation and what are the methods for multithreading in Java with examples. There are mainly two methods for multithreading in Java. An example of multithreading in Java will help you to understand those methods properly. Those two methods are:
Extending Thread Class
Implementing Runnable Interface
Let us try to learn about these methods one by one in a brief to learn about multithreading in Java. If else statement is also an interesting topic to discover. if you’re learning Java then you must read our article.
Let us try to implement the above methods with an example. That will help to understand multithreading in Java for example.
How To Do Multithreading In Java Using Thread Class?
In Java, there is a class present as java.lang.Thread. This is the class that is completely dedicated to the use of threads. A thread class contains constructors and different methods that are used to perform operations and process threads in Java.
In this method, one class will be declared that is going to extend the thread class & implement some function inside. In the thread class, the function should be declared as the run() function because it is the starting point of the execution process.
In the main function, the start() function should be declared to call the thread object and get inside the runnable state of the thread.
Code To Execute Java Multithreading Using Thread Class:
class CodingZap extends Thread {
public void run(){
// Displaying The Thread Which Is Running
System.out.println(Thread.currentThread().getId()+ ": Thread Is Executing");
}}
public class Main{
public static void main(String[] args) {
int n = 5; // Thread Numbers
for (int i = 0; i < n; i++) {
CodingZap obj = new CodingZap(); // Creating Object
obj.start();}}}
Steps of the program:
At first, we need to declare one class that will extend the Thread class to create threads for the program.
Now, inside of that, we need to write the run() method. And Inside the run() method, we have written some statements.
Now, we have taken some values that will be used for calling the Java threads multiple times. For that reason, one for-loop is implemented.
Now, we need to make an object of the declared class. Using that object, we need to start the thread.
Let us try to find out the output of the above code. This will help to understand multithreading in JavaScript.
Output:
From the above output, we can see that the threads are running properly. And random digits are printed in the console which demonstrates the proper use of the thread class.
How To Do Multithreading In Java Using Runnable Interface?
Now, the use of the Runnable interface method is more than similar to the thread class extends form. However, the runnable interface is used because we are not performing extended operations here. Java doesn’t provide multiple inheritance options. So, using the Runnable interface will help to extend other classes if necessary.
In this case, the Java program uses the java.lang.Runnable interface operation rather than using any class. Now, here also the implementation will start from the start() function after we instantiate the thread object until it gets the run() function inside of the program where the thread begins its lifecycle after thread creation.
Code To Execute Java Multithreading Using Runnable Interface:
class CodingZap implements Runnable {
public void run(){
// Displaying The Thread Which Is Running
System.out.println(Thread.currentThread().getId()+ ": Thread Is Executing");
}}
public class Main{
public static void main(String[] args) {
int n = 5; // Thread Numbers
for (int i = 0; i < n; i++) {
Thread obj = new Thread(new CodingZap()); // Creating Object
obj.start();}}}
Steps Of The Program:
Here, We need to declare one class that will implement the Runnable function.
Now, inside of that, we need to write the run() method. Inside the run() method, we have written some statements.
Now, inside the main() method, we need to make an object of the declared class but in a different manner.
We need to first create the object of the thread. Now, we need to cast the declared class object inside of that.
Using that object, we need to start the thread using the start() function. And the implemented loop will call the function multiple times.
Let us try to find out the output of the above code. This will help to understand the example of multithreading in Java.
Output:
The above output is also showing some random numbers printing in the console which is the proof of proper execution of the code. The thread that is running first gives a certain integer number as the output.
How to Implement Multithreading in Java for Loop? Learn more!
By now, I hope you have understood what is a Java thread and how we can create a thread object. Now, let us learn how can we implement multi-threading in Java for a loop with the help of an example.
public class MultithreadedLoop {
public static void main(String[] args) {
int numberOfThreads = 5;
int totalIterations = 7;
for (int i = 0; i < totalIterations; i++) {
final int iterationNumber = i;
Thread thread = new Thread(() -> {
System.out.println("Thread: " + Thread.currentThread().getName() +
", Iteration: " + iterationNumber);
});
thread.start();
}
}
}
Steps of the program:
In this program, we first declare a public class ‘MultithreadedLoop’ that is responsible for the creation of threads.
Static void main() is the entry point of the program.
Next, we have used the for loop that iterates 7 times as the totalIterations variable is assigned the value 7.
Lamba expression is used to create a thread that represents the run method.
The thread. start() method starts the execution.
System.out.println is used for printing the output which can be seen below.
Output:
In this output, we can see that each thread is executed as the loop iterates. Please note that the order of the print statements may differ as the threads are executed concurrently.
Some Commonly Used Thread Methods in Java
Let us now learn what are the most common thread methods that you can use while multithreading in Java. These are given below!
Method Name | Description |
start() | Used for starting the thread execution in a separate path. It has a void modifier. |
run() | It is a JVM method that is used for performing an action in thread |
currentThread() | Used for returning a reference to the current executing thread object |
getName() | Used for returning the name of a thread |
getId() | Used for returning the ID of a thread |
getPriority() | Used for returning the thread priority |
setPriority() | Used for setting or changing a thread priority |
sleep() | Used to pause the execution of a thread for a particular time(in ms) |
suspend() | Used for suspending a thread |
resume() | Used for resuming a suspended thread |
stop() | Used to stop a thread execution. |
dumpStack() | Prints the stack trace for the current thread or running thread |
Where can we use Multithreading in Java Project?
You can use multithreading in a Java project in various scenarios. Some of them are listed below. Have a look!
To implement animation and game logic: In Java projects that include animations or games, you can use multithreading to handle user input concurrently. It can also be used to handle elements like player movements, and game updates, and create fluid animation flow that requires separate threads.
Example: Simple 2D Racing game
To enhance UI responsiveness and server-side programming: Another useful application of multithreading is to handle UI elements and make them responsive based on user interactions or external events. Use multithreading to handle multiple concurrent client requests to increase the scalability of your application.
Example: E-commerce website in java
For background task processing: Another case in which you can use multithreading in your java project is for long-running tasks like File I/O processes, Network operations like making API calls, downloading files, etc.
Example: Video Transcoding Engine
Conclusion:
As we saw, multithreading in Java is a very important topic. A thread is a lightweight process in Java applications. We have to always remember what is multithreading in Java. Multithreading Java helps us to solve difficult problems in the future.
Multithreading in Java with examples is a very important sub-topic of this content. It is advisable to clear the basis of the Java programming language. This will help a lot in the future.
Since you’re learning programming then you must be curious to know about their applications. You can check out C++ applications and attain more knowledge.
So, hope you have liked this piece of article. Share your thoughts in the comments section and let us know if we can improve more.
Key Takeaways:
With the help of this article, we learned what multithreading is in Java and how can we implement it using sample programs.
We saw the difference between single thread and multi-thread in Java and also got to know about their further types like user threads and daemon threads.
We were able to implement multithreading using a for loop in Java and saw how we could use various thread methods for the purpose.
Some most used Java thread methods were also listed in the article for quick reference.
Multithreading has different advantages in Java. It helps in the concurrent execution of sub-programs or threads for better CPU utilization.
It also helps in efficient memory management and sees its purpose in various projects like animations and server-side applications.
