Learn Multithreading in Java With Examples

Table of Contents [show]

Introduction

The act of running a complicated task through multiple independent virtual processing units is known as multithreading in Java. Threads are the name for these objects. Java threads are virtual and share the same process memory location. Since they present a more secure method of carrying out the procedure, virtual threads

Multiprocessing in Java

Java's implementation of multiprocessing only depends on the host computer's available processors. The CPU receives requests for every user-initiated process. registers on the CPU are loaded with information pertaining to the allocated process.

Java only allows for one processor to be used for multiprocessing. As a result, an additional CPU core will start when the user demands the simultaneous execution of another process.

Multitasking can be achieved in two ways:

Process multitasking (multiprocessing)
Multitasking based on threads (Multithreading)

1. Process multitasking (multiprocessing)

Each process has a memory address. In other words, a distinct memory space is assigned to each process.
The process is hard.
The cost of communication during the process is high.
Switching from one process to another takes time to save and load registers, memory maps, update lists, etc.

2. Multitasking based on threads (Multithreading)

Threads share the same address space.
The thread is light.
The cost of inter-thread communication is low.

What is multithreading in Java?

Java's multithreading feature runs two or more threads concurrently to make the most of the CPU. Applications that support multiple threads start and run many threads simultaneously. As a result, in Java, it is also known as concurrency. The threads are connected in a parallel fashion. Memory is not allocated in discrete chunks for each thread. This preserves memory. Additionally, it takes less time to transition between threads' contexts.

What is a thread in Java?

The smallest component of the overall process is a thread. An isolated, virtual, sequential control flow is referred to as a thread. Each thread that participates in the execution of a process uses the same memory. Each thread operates independently of the others to complete tasks.

Sometimes processes may be interdependent for the process to be completed by an intermediate result.

Advantages of Java Multithreading

1) It doesn't block users because threads are independent, and you can do multiple operations simultaneously.

2) It saves time since numerous operations can be completed simultaneously.

3) Because threads are independent of one another, an exception that occurs in one thread won't have an impact on other threads.

The life cycle of a thread in Java

The life cycle of each thread in Java has five different phases. The life cycle stages are listed below.

1. New
2. Executable
3. Run
4. Waiting
5. Dead

New

The first stage is "New". At this stage, it starts a thread. After that, each thread remains in the new state until the thread is assigned to a new task.

Executable

The next stage is the executable stage. This is where a thread is assigned to the task and set to run the task.

Run

The third phase is the implementation phase. Here, a thread starts when control enters the thread, and the thread executes a task and continues to execute until it completes the task.

Waiting

Occasionally, there is a possibility that one process as a whole may depend on another. During such an encounter, the thread may stall due to its dependency on another process due to a quick result. This phase is called the waiting phase.

Dead

Thread termination is the last stage of multithreading process execution in Java. After the process terminates, the JVM automatically declares the thread dead and terminates the thread. This phase is known as the dead thread phase.

Example: In this multithreading program in Java example, we will create a thread and explore the built-in methods available for threads.

demo test package;

```

public class thread_example1 implements Runnable {

    @Override

    public void run() {

    }

    public static void main(String[] args) {

        Thread guruthread1 = new Thread();

        guruthread1.start();

        try {

            guruthread1.sleep(1000);

        } catch (InterruptedException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        guruthread1.setPriority(1);

        int gurupriority = guruthread1.getPriority();

        System.out.println(gurupriority);

        System.out.println("Thread Running");

  }

}

Output:

5 is the Thread priority, and Thread Running is the text which is the output of our code.

Methods of Multithreading in Java

Following are the methods for Multithreading in Java.

Java thread synchronization

There is the asynchronous behaviour of programmes in multithreading. The programme may become inconsistent if one thread is simultaneously writing some data while the other is reading it.

The synchronization approach is used when two or more threads need to access shared resources.

Java provides synchronized methods to implement synchronized behavior.

In this approach, once a thread reaches inside a synchronized block, no other thread can call this method on the same object. All threads must wait until the thread has completed and exited the synchronized block.

In this way, synchronization helps in a multi-threaded application. One thread must wait for the other thread to complete its execution. Only then are other threads allowed to run.

Summary

In this blog, we have seen multi-threaded applications in Java and how to use single-threaded and multi-threaded in Java. Explain multithreading in Java: users are not blocked in multithreading because threads are independent and can perform multiple operations simultaneously. Different stages of the fiber life cycle. We also learned about cross-thread synchronization, which helps the application run smoothly. Multi-threaded programming in Java facilitates many more application tasks.