What is Multithreading in Java?
- The center concept in advanced programming is multithreading, which is the most calculate behind making applications proficient and responsive.
- In straightforward words, multithreading alludes to the capacity of a CPU to execute numerous strings at a time, hence utilizing the accessible assets superior and performing operations quicker.
- The littlest unit of execution in a program could be a string.
- A set of strings that can execute different operations at the same time is utilized in arrange to move forward the execution of applications.
- In Java, multithreading permits different strings to run concurrently inside the same program for executing different assignments.
- Such an capacity is exceptionally vital in circumstances where a few parts of the errand can be run freely, such as when preparing client input, dealing with information, and upgrading the client interface at the same time.
Why Use Multithreading in Java?
Java’s use of multithreading is primarily due to:
- More efficient CPU usage can be achieved by allowing for concurrent execution of multiple threads, particularly on multi-core processors.
- Improved Application Performance: Tasks that are not related can be performed at the same time, resulting in a shorter wait time and better app performance.
- The utilization of multithreading in GUI applications ensures that the user interface remains fluid and responsive, even when performing heavy computations or I/O tasks in the background.
Types of Threads in java:
There are two primary ways to create and work with threads in Java:
1. User Threads:
- Tasks are executed by a Java program using the primary execution thread, which is known as ‘user threads’.
- They are the main threads that drive the application.
- They run in tandem with other threads, running until they are finished.
2. Daemon Threads:
- Users can have threads in the background, which are referred to as daemon and supported by their own thread.
- Their duties are limited to sporadic roles, such as cleaning, filing papers, or clearing clutter.
- Rather than waiting for daemon threads to finish finishing, the JVM shuts down. If only daemon threads are left, the JVM will terminate.
Techniques for generating threads in Java
Two primary approaches for generating and running threads in Java are:
1. Extending the Thread Class:
- You use the following technique to instantiate a subclass of the Thread class and override its run() method.
Here’s an example:
class MyThread extends Thread {
public void run() {
System.out.println(“Thread is running”);
}
}
public class Main {
public static void main(String[] args) {
MyThread t1 = new MyThread();
t1.start(); // Starts the thread
}
}
2. Implementing the Runnable Interface:
- The Runnable interface can be used instead of extending the Thread class, and the run() method can also be defined.
- If the class is already inheriting functionality from another class and needs to implement it in a thread, this approach is preferred.
class MyRunnable implements Runnable {
public void run() {
System.out.println(“Runnable thread is running”);
}
}
public class Main {
public static void main(String[] args) {
MyRunnable r = new MyRunnable();
Thread t = new Thread(r);
t.start();
}
}
Thread Lifecycle
The journey of a thread in Java can be described as follows:
- A thread is formed but hasn’t been initiated yet.
- The thread is set to run but may not be running immediately due to the operating system’s scheduling schedule.
- Waiting for resources or events (such as I/O operations) to occur, and then blocking the thread.
- Erased: The thread has reached its conclusion.
Thread Synchronization
- While multithreading can be advantageous, it also creates complications like data inconsistency when multiple threads access the same resources.
- The implementation of thread synchronization prevents conflicts by limiting resource access to one thread at a time.
- The synchronized keyword is one of the Java functions that ensures only one thread can execute a crucial line of code at arbitrary speed.
Example:
class Counter {
private int count = 0;
public synchronized void increment() {
count++;
}
public int getCount() {
return count;
}
}
Here, Synchronization of the increment method ensures that only one thread can alter the count value simultaneously.
A Practical Multithreading Case Study
- Imagine a situation where java program is processing some user data (Ex. In this program we can split data reading/processing and saving on a number of different threads.
class DataReader implements Runnable {
public void run() {
System.out.println(“Reading data…”);
}
}
class DataProcessor implements Runnable {
public void run() {
System.out.println(“Processing data…”);
}
}
class DataSaver implements Runnable {
public void run() {
System.out.println(“Saving data…”);
}
}
public class Main {
public static void main(String[] args) {
Thread reader = new Thread(new DataReader());
Thread processor = new Thread(new DataProcessor());
Thread saver = new Thread(new DataSaver());
reader.start();
processor.start();
saver.start();
}
}
- In this scenario, each operation is executed in sequence, which reduces the total time needed to complete the task.