Print Odd and Even Numbers Using Threads And Semaphore

Hello Friends,
In this post, we will talk and learn about How to Write a Java program Print Odd and Even Numbers Using Threads And Semaphore.

Here Idea is that Thread-1 has to print Odd numbers and Thread-2 has to print Even numbers in Sequential order as below:

Thread-1:1
Thread-2:2
Thread-1:3
Thread-2:4
Thread-1:5
Thread-2:6
Thread-1:7
Thread-2:8
Thread-1:9
Thread-2:10
Thread-1:11
Thread-2:12
Thread-1:13
Thread-2:14
Thread-1:15
Thread-2:16
Thread-1:17
Thread-2:18
Thread-1:19
Thread-2:20

Resource OddAndEvenNumberGenerator.java is going to share with both the Threads to print odd and even numbers.

package com.kkjavatutorials.resource;

import java.util.concurrent.Semaphore;

public class OddAndEvenNumberGenerator {

	private Semaphore semaphoreOdd = new Semaphore(1);
	private Semaphore semaphoreEven = new Semaphore(0);
	
	public void printOddNumber(int number) {
		try {
			semaphoreOdd.acquire();
			System.out.println(Thread.currentThread().getName()+":"+number);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}finally {
			semaphoreEven.release();
		}
	}
	
	public void printEvenNumber(int number) {
		try {
			semaphoreEven.acquire();
			System.out.println(Thread.currentThread().getName()+":"+number);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}finally {
			semaphoreOdd.release();
		}
	}
}

package com.kkjavatutorials.resource;

import java.util.concurrent.Semaphore;

public class OddAndEvenNumberGenerator {

private Semaphore semaphoreOdd = new Semaphore(1);

private Semaphore semaphoreEven = new Semaphore(0);

public void printOddNumber(int number) {

try {

semaphoreOdd.acquire();

System.out.println(Thread.currentThread().getName()+":"+number);

} catch (InterruptedException e) {

e.printStackTrace();

}finally {

semaphoreEven.release();

}

public void printEvenNumber(int number) {

try {

semaphoreEven.acquire();

System.out.println(Thread.currentThread().getName()+":"+number);

} catch (InterruptedException e) {

e.printStackTrace();

}finally {

semaphoreOdd.release();

}

Source code of OddNumberGenerator.java and EvenNumberGenerator.java

package com.kkjavatutorials.task;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;

public class OddNumberGenerator implements Runnable {

	private OddAndEvenNumberGenerator oddAndEvenNumberGenerator;
	private int totalNumberInSEquence;
	
	public OddNumberGenerator(OddAndEvenNumberGenerator oddAndEvenNumberGenerator, int totalNumberInSEquence) {
		super();
		this.oddAndEvenNumberGenerator = oddAndEvenNumberGenerator;
		this.totalNumberInSEquence = totalNumberInSEquence;
	}

	@Override
	public void run() {
		for (int i = 1; i <= totalNumberInSEquence; i =i+2) {
			oddAndEvenNumberGenerator.printOddNumber(i);
		}
	}
}

package com.kkjavatutorials.task;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;

public class OddNumberGenerator implements Runnable {

private OddAndEvenNumberGenerator oddAndEvenNumberGenerator;

private int totalNumberInSEquence;

public OddNumberGenerator(OddAndEvenNumberGenerator oddAndEvenNumberGenerator, int totalNumberInSEquence) {

super();

this.oddAndEvenNumberGenerator = oddAndEvenNumberGenerator;

this.totalNumberInSEquence = totalNumberInSEquence;

}

@Override

public void run() {

for (int i = 1; i <= totalNumberInSEquence; i =i+2) {

oddAndEvenNumberGenerator.printOddNumber(i);

}

package com.kkjavatutorials.task;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;

public class EvenNumberGenerator implements Runnable {

	private OddAndEvenNumberGenerator oddAndEvenNumberGenerator;
	private int totalNumberInSEquence;
	
	public EvenNumberGenerator(OddAndEvenNumberGenerator oddAndEvenNumberGenerator, int totalNumberInSEquence) {
		super();
		this.oddAndEvenNumberGenerator = oddAndEvenNumberGenerator;
		this.totalNumberInSEquence = totalNumberInSEquence;
	}

	@Override
	public void run() {
		for (int i = 2; i <= totalNumberInSEquence; i = i+2) {
			oddAndEvenNumberGenerator.printEvenNumber(i);
		}
	}
}

package com.kkjavatutorials.task;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;

public class EvenNumberGenerator implements Runnable {

private OddAndEvenNumberGenerator oddAndEvenNumberGenerator;

private int totalNumberInSEquence;

public EvenNumberGenerator(OddAndEvenNumberGenerator oddAndEvenNumberGenerator, int totalNumberInSEquence) {

super();

this.oddAndEvenNumberGenerator = oddAndEvenNumberGenerator;

this.totalNumberInSEquence = totalNumberInSEquence;

}

@Override

public void run() {

for (int i = 2; i <= totalNumberInSEquence; i = i+2) {

oddAndEvenNumberGenerator.printEvenNumber(i);

}

OddEvenNumberPrintByTwoThreadsTest.Java Client program with main Method:

package com.kkjavatutorials.client;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;
import com.kkjavatutorials.task.EvenNumberGenerator;
import com.kkjavatutorials.task.OddNumberGenerator;

/**
 * Print Odd-Even Numbers Using Threads And Semaphore
 * @author KK JavaTutorials
 *
 */
public class OddEvenNumberPrintByTwoThreadsTest {

	public static void main(String[] args) {
		
		int TOTAL_NUMBER_IN_SEQUENCE = 20;
		
		OddAndEvenNumberGenerator oddAndEvenNumberGenerator = new OddAndEvenNumberGenerator();
		
		OddNumberGenerator  oddNumberGenerator = new OddNumberGenerator(oddAndEvenNumberGenerator, TOTAL_NUMBER_IN_SEQUENCE);
		EvenNumberGenerator evenNumberGenerator = new EvenNumberGenerator(oddAndEvenNumberGenerator, TOTAL_NUMBER_IN_SEQUENCE);
		
		Thread t1 = new Thread(oddNumberGenerator, "Thread-1");
		Thread t2 = new Thread(evenNumberGenerator, "Thread-2");
		
		t1.start();
		t2.start();
	}

}

package com.kkjavatutorials.client;

import com.kkjavatutorials.resource.OddAndEvenNumberGenerator;

import com.kkjavatutorials.task.EvenNumberGenerator;

import com.kkjavatutorials.task.OddNumberGenerator;

/**

* Print Odd-Even Numbers Using Threads And Semaphore

* @author KK JavaTutorials

public class OddEvenNumberPrintByTwoThreadsTest {

public static void main(String[] args) {

int TOTAL_NUMBER_IN_SEQUENCE = 20;

OddAndEvenNumberGenerator oddAndEvenNumberGenerator = new OddAndEvenNumberGenerator();

OddNumberGenerator oddNumberGenerator = new OddNumberGenerator(oddAndEvenNumberGenerator, TOTAL_NUMBER_IN_SEQUENCE);

EvenNumberGenerator evenNumberGenerator = new EvenNumberGenerator(oddAndEvenNumberGenerator, TOTAL_NUMBER_IN_SEQUENCE);

Thread t1 = new Thread(oddNumberGenerator, "Thread-1");

Thread t2 = new Thread(evenNumberGenerator, "Thread-2");

t1.start();

t2.start();

}

If you run OddEvenNumberPrintByTwoThreadsTest.Java then we get below output.

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