Different Ways of Multithreading in Java

Multithreading is a process of executing multiple threads concurrently within a single program. In Java, multithreading is implemented with the help of threads. Java threads are lightweight processes that run within a single Java application. Threads are similar to a single process but faster and more efficient than a single process.

Threads can be used to improve the performance of a program by allowing multiple tasks to be executed concurrently. This can be especially beneficial when running multiple applications simultaneously, as each thread can be managed independently.

Multithreading in Java can be implemented in two ways: using the Java Thread class or the Java Runnable interface. The many methods for creating multithreading in Java will be covered in this article.

Thread Class in Java

The simplest method of multithreading implementation in Java is using the Java Thread class. Threads are produced by extending the Thread class and overriding the run() function. The thread's code will be executed using the run() function.When creating a thread, the thread’s priority can be set, which determines the order in which the threads are executed. Higher priority threads will be processed before lower priority threads. Additionally, the thread’s name can be set, which makes it easier to identify and debug the thread.

Once the thread is created, the start() method can be called to start the thread’s execution. The thread will then execute until the run() method returns.

The Thread class is the most basic way to create Java threads. It is the most commonly used approach for multithreading. This class provides several methods and constructors that allow you to create and manage threads in your Java programs. A simple example of how to create a thread using the Thread class is given below:

public class MyThread extends Thread { 
    public void run() { 
       // code to be executed by the thread 
    }
	public static void main(String s[])
	{
		Thread t1 =new Thread();
		t1.run();
	} 
} 

Calling the start() function will initiate the thread after it has been created. The thread's code will be executed using the run() function. The stop() function must be used to end the thread.

Java Runnable Interface

The Java Runnable interface is another way of implementing multithreading in Java. The run function is all that the Runnable interface has to provide (). The thread will execute the code in this procedure. When creating a thread with the Runnable interface, the thread’s priority and name can be set similarly to the Thread class. Additionally, the thread can be created with an anonymous inner class, which simplifies the code.

Once the thread is created, it can be started by passing it to a Thread object. The Thread object will then call the thread’s run() method, and the thread will start executing.

Multithreading.java

class Multithreading implements Runnable {
	public void run()
	{
		try {
			System.out.println("Thread " + Thread.currentThread().getId()+ " is running");
		}
		catch (Exception e) {
	        System.out.println("Exception raised and caught");
		}
	}
}


class Multithreading {
	public static void main(String[] args)
	{
		int n = 6; 
		for (int j = 0; j < n; j++) {
			Thread o1	= new Thread(new Multithreading());
			o1.start();
		}
	}
}

Output

Thread 13 is running
Thread 10 is running
Thread 12 is running
Thread 11 is running
Thread 14 is running
Thread 15 is running

Thread Pooling

Thread pooling is a way of managing threads and scheduling tasks. Thread pooling allows multiple tasks to be queued up and executed by a limited number of threads.

By enabling concurrent task execution, thread pooling can help a software run more efficiently. Additionally, thread pooling can reduce the time it takes to execute a task, as the tasks can be executed in parallel.

Thread Pooling in Java can be implemented using the java.util.concurrent.Executors class. This class provides several methods for creating and managing thread pools.

Synchronization

Synchronization is a way of ensuring that multiple threads access shared data safely and consistently. Synchronization can be used to make sure that only one thread at a time can access a shared resource when numerous threads are using it.

Java's synchronised keyword may be used to achieve synchronisation. Only one thread can access the shared resource at once thanks to the crucial section that can be created using this keyword.Additionally, synchronization can be used to ensure that a thread completes a task before another thread begins executing. This is known as thread synchronization and can be used to ensure that tasks are executed in the correct order.

Inter-thread Communication

Inter-thread communication is a way of allowing multiple threads to communicate with each other. This may be applied to coordinate task execution and transmit messages between threads.

Java's wait(), notify(), and notifyAll() methods can be used to implement inter-thread communication. These methods allow one thread to wait for another thread to finish executing and allow threads to pass messages between each other.

Volatile Variables

Volatile variables ensure that a thread’s view of a variable is up to date. When multiple threads access a variable, the variable’s value can become out of sync, as different threads can view the variable differently.

Volatile variables can be used to ensure that all threads have the same view of a variable. When a volatile variable is accessed, the latest value of the variable is always read from memory. This ensures that all threads have the same view of the variable.

Types of Threads in Java

In Java, there are two types of threads: user-defined and daemon threads.

User-Defined Threads

The application developer creates user-defined threads. These threads are responsible for performing the tasks defined by the application. User-defined threads are also known as non-daemon threads because they are not terminated by the system but are allowed to run until the application terminates.

Daemon Threads

Daemon threads are created by the Java Virtual Machine (JVM) and are responsible for performing tasks that are not directly related to the application logic. These threads are also known as system threads because the system manages them. Daemon threads are terminated when the application terminates.

Conclusion

In this article, we have discussed the different ways of implementing multithreading in Java. Multithreading in Java can be implemented using the Thread class, the Runnable interface, thread pooling, synchronization, inter-thread communication, and volatile variables. By understanding the different ways of implementing multithreading in Java, developers can improve the performance of their applications and ensure that their applications are reliable and efficient.