Tutorial Playlist

Java Tutorial for Beginners

Overview

10 Reasons That Explain Why You Need to Learn Java

Lesson - 1

What is Java: A Beginners Guide To Java

Lesson - 2

What Is JDK? Why Do We Need It?

Lesson - 3

One-Stop Solution for Java Installation in Windows

Lesson - 4

How to Get Started With Eclipse IDE?

Lesson - 5

What Are Java Strings And How to Implement Them?

Lesson - 6

Arrays In Java: Declare, Define, and Access Array

Lesson - 7

What Are Java Collections and How to Implement Them?

Lesson - 8

What Are Java Classes and Objects and How Do You Implement Them?

Lesson - 9

How to Implement the Revolutionary OOPs Concepts in Java

Lesson - 10

What is Encapsulation in Java and How to Implement It?

Lesson - 11

What is an Abstract Class in Java and How to Implement It?

Lesson - 12

What is Inheritance in Java and How to Implement It

Lesson - 13

What is Java Interface and Why it's Needed?

Lesson - 14

What is Polymorphism in Java and How to Implement It?

Lesson - 15

What is a Java Lambda Expression and How to Implement It?

Lesson - 16

Your One-Stop Solution for Multithreading in Java

Lesson - 17

The Differences Between C++ and Java That You Need To Know

Lesson - 18

Java vs. Python: Which is the Best Programming Language?

Lesson - 19

Java vs JavaScript: Know The 8 Major Differences

Lesson - 20

Top 25 Pattern Programs in Java For Printing Numbers

Lesson - 21

Java EE Tutorial: All You Need To Know About Java EE

Lesson - 22

What is Exception Handling in Java?

Lesson - 23

What Is Java JDBC? The Complete Reference

Lesson - 24

What is Java API and The Need for Java APIs?

Lesson - 25

Introduction To Java Servlets and Its Life-Cycle

Lesson - 26

10 Best Java Frameworks You Should Know in 2021

Lesson - 27

Top 10 Brilliant Java Project Ideas You Need to Know

Lesson - 28

Top 60 Java Interview Questions and Answers in 2021

Lesson - 29

Java Programming: The Complete Reference You Need

Lesson - 30

All You Need to Know to Implement JUnit Testing in Java

Lesson - 31

What Is Junit? a Look Into the Best Java Testing Framework

Lesson - 32
Your One-Stop Solution for Multithreading in Java

Multithreading in Java is an act of executing a complex process using virtual processing entities independent of each other. These entities are called threads. Threads in Java are virtual and share the same memory location of the process. As the threads are virtual, they exhibit a safer way of executing a process.

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What are Multitasking and the Types of Multitasking?

Multitasking is an approach to minimize execution time and maximize CPU utilization by executing multiple tasks simultaneously. You can achieve the process of multitasking in Java using two methods, as described below.

Multithreading-in-Java-Mutlitasking

Multiprocessing in Java 

Multiprocessing in Java is purely based on the number of processors available on the host computer. Every process initiated by the user is sent to the CPU (processor). It loads the registers on the CPU with the data related to the assigned process.

To perform multiprocessing in Java, the user needs one processor. Therefore, when the user requests the simultaneous execution of the second process, the alternate CPU core gets triggered and executes the process.

Multithreading in Java

Multithreading in Java is a similar approach to multiprocessing. However, there are some fundamental differences between the two. Instead of a physical processor, multithreading involves virtual and independent threads.

It assigns each process with one or more threads based on their complexity. Each thread is virtual and independent of the other. This makes process execution much safer. If a thread or two are terminated during an unexpected situation, the process execution will not halt.

In the next section of this Multithreading in Java tutorial, you will learn about a thread in Java.

What is a Thread in Java?

A thread is the smallest segment of an entire process. A thread is an independent, virtual and sequential control flow within a process. In process execution, it involves a collection of threads, and each thread shares the same memory. Each thread performs the job independently of another thread. 

Multithreading-in-Java-what-is-a-thread.

Sometimes, the processes might be interdependent for an intermediate result to finish the process.

In the next part of the Multithreading in Java tutorial, you will learn about the Lifecycle of a Thread.

Lifecycle of a Thread in Java

The lifecycle of each thread in Java has five different stages. You will look into each one of those stages in detail. The Stages of the Lifecycle are mentioned below.

  • New
  • Runnable
  • Running
  • Waiting
  • Dead

Multithreading-in-Java-Thread-lifecycle.

New

The first stage is "New". This stage is where it initiates the thread. After that, every thread remains in the new state until the thread gets assigned to a new task.

Runnable

The next stage is the runnable stage. Here, a thread gets assigned to the task and sets itself for running the task. 

Running

The third stage is the execution stage. Here, the thread gets triggered as control enters the thread, and the thread performs a task and continues the execution until it finishes the job. 

Waiting

At times, there is a possibility that one process as a whole might depend on another. During such an encounter, the thread might halt for an intermediate result because of its dependency on a different process. This stage is called the Waiting Stage.

Dead

The final stage of the process execution with Multithreading in Java is thread termination. After it terminates the process, the JVM automatically declares the thread dead and terminates the thread. This stage is known as the dead thread stage.

Now that you learned about the thread and its life cycle, move ahead and understand multithreading in Java.

What is Multithreading in Java?

So far, you have looked into the process, thread, and thread lifecycle. You understood that a computer executes a task via a thread. Now, you will learn the process of multithreading in Java.

As the name suggests, multithreading in Java executes a complex process by running a collection of threads simultaneously. Each thread belongs to the Java.lang.Thread class. The thread class overrides the run() method and executes the process.

In the next part, you will get to know about the methods of Multithreading in Java. 

Methods of Multithreading in Java

Following are the methods for Multithreading in Java.

start()

The start method initiates the execution of a thread

currentThread()

The currentThread method returns the reference to the currently executing thread object.

run()

The run method triggers an action for the thread

isAlive() 

The isAlive method is invoked to verify if the thread is alive or dead

sleep()

The sleep method is used to suspend the thread temporarily

yield()

The yield method is used to send the currently executing threads to standby mode and runs different sets of threads on higher priority

suspend()

The suspend method is used to instantly suspend the thread execution

resume()

The resume method is used to resume the execution of a suspended thread only

interrupt()

The interrupt method triggers an interruption to the currently executing thread class

destroy()

The destroy method is invoked to destroy the execution of a group of threads

stop()

The stop method is used to stop the execution of a thread

After the methods of Multithreading in Java, you will go through an example based on Multithreading in Java.

Example for Multithreading in Java

The following is an example based on multithreading in Java using the runnable interface.

//Code

package multithreading;

class ThreadCount extends Thread{

ThreadCount(){

super("Overriding Thread Class");

System.out.println("New thread created" + this);

start();

}

public void run(){ //Run Method

    try{

        for (int i=0 ;i<10;i++){

System.out.println("New thread created" + this);

Thread.sleep(1500);

        }

    }

    catch(InterruptedException e){

System.out.println("Currently executing thread is interrupted");

}

System.out.println("Currently executing thread run is terminated" );

}

}

public class MultiThreading{

public static void main(String args[]){

ThreadCount C = new ThreadCount();

try{

while(C.isAlive()){

System.out.println("Main Method Thread will be alive, until it's Child Thread stays alive");

Thread.sleep(2500); //Sleep method

}

}

catch(InterruptedException e){

System.out.println("Main Method thread is interrupted");

}

System.out.println("Main Method's thread run is terminated" );

}

}

//Output:

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

New thread createdThread[Overriding Thread Class,5,main]

Main Method Thread will be alive, until it's Child Thread stays alive

Currently executing thread run is terminated

Main Method's thread run is terminated

Next, you will learn the differences between multiprocessing and multithreading in java.

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Multiprocessing vs. Multithreading in Java

The following table explains the fundamental differences between Multiprocessing and Multithreading in Java

Multiprocessing

Multithreading

Multiprocessing requires multiple physical processors for executing a complex process.

Multithreading in Java requires virtual threads. These threads are independent of each other.

Multiprocessing involves two types, namely symmetric and asymmetric multiprocessing.

There are no different types of multithreading in Java

Multiprocessing is heavy and time-consuming

Multithreading in Java is completely light and a timesaving procedure 

In multiprocessing, each process owns a separate memory location

In the process of Multithreading in Java, Threads share the same memory location 

If one processor is compromised, then the respective process of that CPU or the entire process may collapse 

Since all the threads are independent of each other, if any thread is compromised, then the entire process will not be affected by any means.

Next, you will learn about the advantages and disadvantages of multithreading in java.

Advantages of Multithreading in Java

Mentioned below are the few advantages of Multithreading in Java:

Java-multithreading-advantages.

  • Multithreading in Java improves the performance and reliability
  • Multithreading in Java minimizes the execution period drastically
  • There is a smooth and hassle-free GUI response while using Multithreading in Java
  • The software maintenance cost is lower
  • The CPU and other processing resources are modes judiciously used

Disadvantages of Multithreading in Java

Following are a few disadvantages of Multithreading in Java:

Java-multithreading-disadvantages

  • Multithreading in Java poses complexity in code debugging
  • Multithreading in Java increases the probability of a deadlock in process execution 
  • The results might be unpredictable in some worst-case scenarios
  • Complications might occur while code is being ported 

With that, you have come to an end of the “Multithreading in Java” tutorial.

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Conclusion

Java Development Kit could be your next step in the journey of learning Java. JDK is the fundamental tool in Java which includes the Java Run-time Environment and Java Virtual Machine.

If you are interested in learning in-depth concepts of the Java programming language and want to get certified as an Expert Java developer, then feel free to visit Simplilearn's Java training and certification program on our official website. The program is designed and delivered by real-time IT experts offering online learning. You can also take a look at Simplilearn's Full Stack Java Developer Master's Program!

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