Multithreading in Java: A Beginner’s Guide In 5 Easy Steps

WHAT IS MULTITHREADING IN JAVA? AN INTRODUCTION

If you’re an aspiring Java developer, you might have come across the phrase ‘multithreading program’ in your daily life. So, what is multithreading in Java? Multithreading in Java is a feature that enables the simultaneous running of two or more parts of a program by making optimum use of the processing unit. Each thread in a program is defined with a path for execution in a multithreading program in Java; these threads are run concurrently. Before we move ahead, these are some of the methods used in thread class:

• getName()

It is used for Obtaining a thread’s name

• getPriority()

-It obtains a thread’s priority

• isAlive()

It determines if a thread is still running

• join()-

It waits for a thread to terminate

• run()

Entry point for the thread

• sleep()
• Suspend a thread for a period of time
• start()
• Start a thread by calling its run() method

If you are still wondering – What is a multithreading program? – then these methods will be used ahead in the article, after understanding the basics of Java multithreading in depth. All of these are explained below in a detailed manner.

1. What are the benefits of Multithreading in Java?
2. What are the types of Multithreading in Java?
3. How to create multiple threads in java?
4. What is a Multithreading Example in Java?
5. The Cycle of a thread in various phases

1. WHAT ARE THE BENEFITS OF MULTITHREADING IN JAVA?

A multithreading program in Java enables multiple parts of a program to be executed simultaneously. These parts, known as threads, are lightweight processes readily available throughout the process. A Multithreading program in Java, therefore, leads to maximum use of CPU by multitasking. Some of the advantages of multithreading in Java are mentioned below.

• Multithreading programs in Java improve the functioning of simultaneously running multiple operations for computation.
• Multithreading programs increase the responsiveness of the program. When multiple threads run, different threads get executed, and it freezes the program. But, multithreading in java, keeps the application running, by keeping other pending processes running simultaneously.
•  Multithreading programs increase the server response rate. Multithreading in Java ensures that the large and complex requests don’t get stranded and creating multiple threads in Java does not block any other requests. It Increases the overall output of the server.
• Multithreading in Java minimizes the system use, as the threads are easy to maintain, manage, and require less overhead to create.
• Multithreading in Java improves the program structure by making it simpler and easier to access. These simplified threads can be used in media applications which are high server classes, to modify or improve the structure of these complicated structures with ease.
• Multithreading program helps create better communication as a resource.
• Multithreading in Java provides synchronization.
• Multithreading in Java enhances data sharing with high speed. This is all possible through sharing the space with a similar data address.

2. WHAT ARE THE TYPES OF MULTITHREADING IN JAVA?

There are two ways of creating multiple threads in Java to harness the maximum output of the CPU which are used depending upon the needs of the program structure.

A) Process-Based Multitasking

• Each process will be assigned a different address for their memory.
• The process of carrying several threads results in having a heavyweight.
• This weight inversely affects the changing time from one process to another because of saving the memory maps, updating lists, and loading registers.
• The cost of communication between the process is remarkably high.

B) Thread Based Multitasking

• As compared to process-based multitasking, in thread-based multitasking, all threads have a shared address space.
• A thread is quite lightweight.
• A thread is a subset of a process which makes it cheaper in terms of communicating.

3. HOW TO CREATE MULTIPLE THREADS IN JAVA?

Java provides both a runnable interface and class thread that are available to access in the Java language package. These methods are explained with examples for a better understanding of the code required.

There are two ways to achieve multithreading in java

A) By creating a runnable Interface and overriding a run() method

It is used when a thread is needed to be created, and it is the most recommended process to follow.

B) By creating a thread Interface and overriding a start() method

It is used when your process requires more functionalities for a thread, a thread interface is implemented.

4. What is a Multithreading Example in Java?

Go through these programs to understand how multithreading works.

class Count implements Runnable

{

   Thread mythread ;

   Count()

   {

      mythread = new Thread(this, “my runnable thread”);

      System.out.println(“my thread created” + mythread);

      mythread.start();

   }

   public void run()

   {

      try

      {

        for (int i=0 ;i<10;i++)

        {

       System.out.println(“Printing the count ” + i);

       Thread.sleep(1000);

        }

     }

     catch(InterruptedException e)

     {

        System.out.println(“my thread interrupted”);

     }

     System.out.println(“mythread run is over” );

   }

}

class RunnableExample

{

    public static void main(String args[])

    {

       Count cnt = new Count();

       try

       {

       while(cnt.mythread.isAlive())

       {

         System.out.println(“Main thread will be alive till the child thread is live”);

         Thread.sleep(1500);

       }

       }

       catch(InterruptedException e)

       {

       System.out.println(“Main thread interrupted”);

       }

       System.out.println(“Main thread run is over” );

    }

}

Output:

my thread createdThread[my runnable thread,5,main]

Main thread will be alive till the child thread is live

Printing the count 0

Printing the count 1

Main thread will be alive till the child thread is live

Printing the count 2

Main thread will be alive till the child thread is live

Printing the count 3

Printing the count 4

Main thread will be alive till the child thread is live

Printing the count 5

Main thread will be alive till the child thread is live

Printing the count 6

Printing the count 7

Main thread will be alive till the child thread is live

Printing the count 8

Main thread will be alive till the child thread is live

Printing the count 9

mythread run is over

Main thread run is over

Example of Thread Class

class Count extends Thread

{

   Count()

   {

     super(“my extending thread”);

     System.out.println(“my thread created” + this);

     start();

   }

   public void run()

   {

     try

     {

        for (int i=0 ;i<10;i++)

        {

        System.out.println(“Printing the count ” + i);

        Thread.sleep(1000);

        }

     }

     catch(InterruptedException e)

     {

        System.out.println(“my thread interrupted”);

     }

     System.out.println(“My thread run is over” );

   }

}

class ExtendingExample

{

   public static void main(String args[])

   {

      Count cnt = new Count();

      try

      {

         while(cnt.isAlive())

         {

        System.out.println(“Main thread will be alive till the child thread is live”);

        Thread.sleep(1500);

         }

      }

      catch(InterruptedException e)

      {

        System.out.println(“Main thread interrupted”);

      }

      System.out.println(“Main thread’s run is over” );

   }

}

Output:

my thread createdThread[my runnable thread,5,main]

Main thread will be alive till the child thread is live

Printing the count 0

Printing the count 1

Main thread will be alive till the child thread is live

Printing the count 2

Main thread will be alive till the child thread is live

Printing the count 3

Printing the count 4

Main thread will be alive till the child thread is live

Printing the count 5

Main thread will be alive till the child thread is live

Printing the count 6

Printing the count 7

Main thread will be alive till the child thread is live

Printing the count 8

Main thread will be alive till the child thread is live

Printing the count 9

mythread run is over

Main thread run is over

5. THE CYCLE OF A THREAD IN VARIOUS PHASES

Threading in Java, at any point of time, exists in any one of the following states.

1. New: A thread begins its life cycle in the new state. It remains in this state until the start() method is called on it.
2. Runnable: After the invocation of start() method on a new thread, the thread becomes runnable. A multithreading program in java gives each individual thread a fixed amount of time. Each thread runs for a short time, then pauses and provides the CPU with a new thread so that other threads can run. When this is achieved, all threads are ready to run, waiting for the CPU, and the presently running thread lies in a runnable state.
3. Terminated: A thread enters the terminated state when it completes its task.
4. Running: A thread is in running state if the thread scheduler has selected it.
5. Waiting: A thread is waiting if it waits for another thread to perform a task. In this stage, the thread is still alive. For instance, when a thread awaits the completion of I/O, it is blocked. The Thread Scheduler is responsible for reactivating a blocked/waiting thread and scheduling it. A thread in this state cannot proceed until it is transferred into a working state. No CPU cycle is consumed by any thread in these states.

CONCLUSION

Hope you found this article helpful in understanding how multithreading in Java works. If you are interested in learning more about multithreading in Java and Software Development, our Master Certificate in Full Stack Development program can give you a comprehensive learning experience. It is an online 170-hour-long course, which is the first & only program on Full Stack Development with Automation and AWS Cloud and is highly in demand among Full Stack learners. Plus, it also offers learners guaranteed placement upon successful completion!

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