Creating Multi-Threaded Applications: A Comprehensive Guide

1. Introduction ……………………………………………………………………….. 3
2. Understanding Multi-Threaded Applications … 5

2.1 What is Multi-Threading? ……………………………… 6
2.2 Benefits of Multi-Threading …………………….. 7
2.3 Key Methods in Multi-Threading ……………….. 8

3. Building a Multi-Threaded Application …………… 10

3.1 Setting Up the Project …………………………………… 11
3.2 Creating the MyCounter Class ………………………. 13
3.3 Implementing the Main Method ………………………. 16
3.4 Adding Thread Sleep ……………………………………………. 19
3.5 Measuring Execution Time ……………………………… 21

4. Synchronous vs. Multi-Threaded Execution …. 24
5. Conclusion ……………………………………………………………………….. 28
6. Additional Resources ………………………………………………. 29

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Introduction

In the rapidly evolving world of software development, understanding how to effectively manage multiple tasks simultaneously is crucial. Multi-threaded applications enable developers to perform multiple operations concurrently, enhancing performance and responsiveness. This eBook delves into the intricacies of multi-threaded applications, guiding you through the creation of a simple multi-threaded program. Whether you’re a beginner or a developer with basic knowledge, this guide offers a clear and concise pathway to mastering multi-threading in Java.

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Understanding Multi-Threaded Applications

What is Multi-Threading?

Multi-threading is a programming technique that allows multiple threads to run concurrently within a single process. Each thread represents an independent path of execution, enabling tasks to be performed simultaneously. This is particularly beneficial for applications that require high performance and responsiveness, such as web servers, gaming engines, and real-time data processing systems.

Benefits of Multi-Threading

Benefit	Description
Enhanced Performance	Allows multiple operations to be executed in parallel, reducing overall execution time.
Improved Responsiveness	Keeps applications responsive by performing background tasks without interrupting the main process.
Resource Utilization	Maximizes CPU usage by distributing tasks across multiple threads.
Scalability	Facilitates the creation of scalable applications capable of handling increased workloads.

Key Methods in Multi-Threading

Understanding the fundamental methods associated with multi-threading is essential for effective implementation. Some of the key methods include:

start(): Initiates a new thread.
run(): Contains the code that the thread executes.
sleep(long millis): Pauses the thread for a specified duration.
wait(): Causes the current thread to wait until another thread invokes notify().
yield(): Suggests that the current thread is willing to yield its current use of a processor.

These methods form the backbone of thread management and synchronization in Java.

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Building a Multi-Threaded Application

Setting Up the Project

To begin building our multi-threaded application, we’ll set up a Java project. Ensure that you have Java Development Kit (JDK) installed on your machine. Using an Integrated Development Environment (IDE) like IntelliJ IDEA or Eclipse can simplify the process.

Project Structure:

S12L02 - Creating thread by extending the thread class/
├── pom.xml
├── src/
│   ├── main/
│   │   └── java/
│   │       └── org/
│   │           └── studyeasy/
│   │               ├── Main.java
│   │               └── MyCounter.java
│   └── test/
│       └── java/
├── target/

S12L02 - Creating thread by extending the thread class/

├── pom.xml

├── src/

│ ├── main/

│ │ └── java/

│ │ └── org/

│ │ └── studyeasy/

│ │ ├── Main.java

│ │ └── MyCounter.java

│ └── test/

│ └── java/

├── target/

Note: The pom.xml file is used for project configuration in Maven.

Creating the MyCounter Class

The MyCounter class serves as the foundation of our multi-threaded application. It holds the logic for counting and displaying iteration values.


package org.studyeasy;

public class MyCounter {
    private int threadNumber;

    // Constructor
    public MyCounter(int threadNumber) {
        this.threadNumber = threadNumber;
    }

    // Method to perform counting
    public void countMe() {
        for (int i = 0; i < 10; i++) {
            System.out.println("Thread " + threadNumber + ": Iteration " + i);
        }
    }
}

package org.studyeasy;

public class MyCounter {

private int threadNumber;

// Constructor

public MyCounter(int threadNumber) {

this.threadNumber = threadNumber;

}

// Method to perform counting

public void countMe() {

for (int i = 0; i < 10; i++) {

System.out.println("Thread " + threadNumber + ": Iteration " + i);

}

Explanation:

threadNumber: Identifies the thread, aiding in distinguishing output from multiple threads.
Constructor: Initializes the threadNumber.
countMe(): Iterates from 0 to 9, printing the current thread number and iteration count.

Implementing the Main Method

The Main class orchestrates the creation and execution of multiple MyCounter instances.


package org.studyeasy;

public class Main {
    public static void main(String[] args) throws InterruptedException {
        // Creating first counter
        MyCounter counter1 = new MyCounter(1);
        counter1.countMe();

        // Displaying separator
        System.out.println("**********");

        // Creating second counter
        MyCounter counter2 = new MyCounter(2);
        counter2.countMe();
    }
}

package org.studyeasy;

public class Main {

public static void main(String[] args) throws InterruptedException {

// Creating first counter

MyCounter counter1 = new MyCounter(1);

counter1.countMe();

// Displaying separator

System.out.println("**********");

// Creating second counter

MyCounter counter2 = new MyCounter(2);

counter2.countMe();

}

Explanation:

counter1 & counter2: Instantiate MyCounter objects with distinct thread numbers.
countMe(): Invokes the counting method for each counter.
Separator: Enhances readability by distinguishing outputs from different threads.

Output:

Thread 1: Iteration 0
Thread 1: Iteration 1
...
Thread 1: Iteration 9
**********
Thread 2: Iteration 0
Thread 2: Iteration 1
...
Thread 2: Iteration 9

Thread 1: Iteration 0

Thread 1: Iteration 1

...

Thread 1: Iteration 9

**********

Thread 2: Iteration 0

Thread 2: Iteration 1

...

Thread 2: Iteration 9

Adding Thread Sleep

To simulate processing delays and observe synchronous execution, we’ll introduce the sleep method.


package org.studyeasy;

public class MyCounter {
    private int threadNumber;

    // Constructor
    public MyCounter(int threadNumber) {
        this.threadNumber = threadNumber;
    }

    // Method to perform counting with sleep
    public void countMe() throws InterruptedException {
        for (int i = 0; i < 10; i++) {
            System.out.println("Thread " + threadNumber + ": Iteration " + i);
            Thread.sleep(500); // Pauses the thread for 500 milliseconds
        }
    }
}

package org.studyeasy;

public class MyCounter {

private int threadNumber;

// Constructor

public MyCounter(int threadNumber) {

this.threadNumber = threadNumber;

}

// Method to perform counting with sleep

public void countMe() throws InterruptedException {

for (int i = 0; i < 10; i++) {

System.out.println("Thread " + threadNumber + ": Iteration " + i);

Thread.sleep(500); // Pauses the thread for 500 milliseconds

}

Explanation:

Thread.sleep(500): Introduces a 500-millisecond pause after each iteration, simulating processing time.
throws InterruptedException: Indicates that the method can throw an InterruptedException, necessitating exception handling in the main method.

Updated Main Method:


package org.studyeasy;

public class Main {
    public static void main(String[] args) throws InterruptedException {
        // Creating first counter
        MyCounter counter1 = new MyCounter(1);
        counter1.countMe();

        // Displaying separator
        System.out.println("**********");

        // Creating second counter
        MyCounter counter2 = new MyCounter(2);
        counter2.countMe();
    }
}

package org.studyeasy;

public class Main {

public static void main(String[] args) throws InterruptedException {

// Creating first counter

MyCounter counter1 = new MyCounter(1);

counter1.countMe();

// Displaying separator

System.out.println("**********");

// Creating second counter

MyCounter counter2 = new MyCounter(2);

counter2.countMe();

}

Output with Sleep:

Thread 1: Iteration 0
(Thread pauses for 500ms)
Thread 1: Iteration 1
...
Thread 1: Iteration 9
**********
Thread 2: Iteration 0
(Thread pauses for 500ms)
Thread 2: Iteration 1
...
Thread 2: Iteration 9
Total time required for processing: 10 seconds

Thread 1: Iteration 0

(Thread pauses for 500ms)

Thread 1: Iteration 1

...

Thread 1: Iteration 9

**********

Thread 2: Iteration 0

(Thread pauses for 500ms)

Thread 2: Iteration 1

...

Thread 2: Iteration 9

Total time required for processing: 10 seconds

Note: The total time aligns with the cumulative sleep durations, highlighting synchronous execution.

Measuring Execution Time

To assess the performance impact of synchronization, we’ll measure the total execution time.


package org.studyeasy;

public class Main {
    public static void main(String[] args) throws InterruptedException {
        long startTime = System.currentTimeMillis();

        // Creating first counter
        MyCounter counter1 = new MyCounter(1);
        counter1.countMe();

        // Displaying separator
        System.out.println("**********");

        // Creating second counter
        MyCounter counter2 = new MyCounter(2);
        counter2.countMe();

        long endTime = System.currentTimeMillis();
        System.out.println("Total time required for processing: " + (endTime - startTime)/1000 + " seconds");
    }
}

package org.studyeasy;

public class Main {

public static void main(String[] args) throws InterruptedException {

long startTime = System.currentTimeMillis();

// Creating first counter

MyCounter counter1 = new MyCounter(1);

counter1.countMe();

// Displaying separator

System.out.println("**********");

// Creating second counter

MyCounter counter2 = new MyCounter(2);

counter2.countMe();

long endTime = System.currentTimeMillis();

System.out.println("Total time required for processing: " + (endTime - startTime)/1000 + " seconds");

}

Explanation:

startTime & endTime: Capture the system’s current time before and after execution.
Total Time Calculation: Subtracts startTime from endTime to determine the total processing duration.

Sample Output:

Thread 1: Iteration 0
...
Thread 1: Iteration 9
**********
Thread 2: Iteration 0
...
Thread 2: Iteration 9
Total time required for processing: 10 seconds

Thread 1: Iteration 0

...

Thread 1: Iteration 9

**********

Thread 2: Iteration 0

...

Thread 2: Iteration 9

Total time required for processing: 10 seconds

Note: The total time aligns with the cumulative sleep durations, highlighting synchronous execution.

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Synchronous vs. Multi-Threaded Execution

In the current implementation, the application runs synchronously, meaning each thread completes its execution before the next begins. This results in a cumulative processing time proportional to the number of threads.

Synchronous Execution Characteristics:

Sequential Processing: One thread executes at a time.
Predictable Behavior: Easy to track execution flow.
Longer Processing Time: Total time increases with the number of threads.

Multi-Threaded Execution Advantages:

Concurrent Processing: Multiple threads run simultaneously.
Reduced Total Time: Execution time decreases as threads operate in parallel.
Enhanced Responsiveness: Applications remain responsive, especially in GUI applications.

To transition from synchronous to multi-threaded execution, we’ll leverage Java’s Thread class or implement the Runnable interface, allowing threads to run concurrently.

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Conclusion

This guide provided a foundational understanding of multi-threaded applications in Java. By creating a simple MyCounter class and orchestrating its execution in the Main class, we explored the basics of thread creation, synchronization, and performance measurement. While the synchronous approach offers simplicity, embracing multi-threading can significantly enhance application performance and responsiveness. As you continue your journey, delving deeper into thread management, synchronization mechanisms, and advanced concurrency utilities will empower you to build robust and efficient applications.

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Note: That this article is AI generated.

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Additional Resources

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S12L02 – Creating thread by extending the thread class

Creating Multi-Threaded Applications: A Comprehensive Guide

Table of Contents

Introduction

Understanding Multi-Threaded Applications

What is Multi-Threading?

Benefits of Multi-Threading

Key Methods in Multi-Threading

Building a Multi-Threaded Application

Setting Up the Project

Creating the MyCounter Class

Implementing the Main Method

Adding Thread Sleep

Measuring Execution Time

Synchronous vs. Multi-Threaded Execution

Conclusion

Additional Resources