Spring and Java Thread example

Java thread images

Here are 3 examples to show you how to do “threading” in Spring. See the code for self-explanatory.

1. Spring + Java Threads example

Create a simple Java thread by extending Thread, and managed by Spring’s container via @Component. The bean scope must be “prototype“, so that each request will return a new instance, to run each individual thread.

PrintThread.java

package com.mkyong.thread;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("prototype")
public class PrintThread extends Thread{

	@Override
	public void run() {
		
		System.out.println(getName() + " is running");
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println(getName() + " is running");
	}

}
AppConfig.java

package com.mkyong.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(basePackages="com.mkyong.thread")
public class AppConfig{
}
App.java

package com.mkyong;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import com.mkyong.config.AppConfig;
import com.mkyong.thread.PrintThread;

public class App 
{
    public static void main( String[] args )
    {

    	ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);
    	
    	PrintThread printThread1 = (PrintThread) ctx.getBean("printThread");
    	printThread1.setName("Thread 1");
    	
    	PrintThread printThread2 = (PrintThread) ctx.getBean("printThread");
    	printThread2.setName("Thread 2");
    	
    	PrintThread printThread3 = (PrintThread) ctx.getBean("printThread");
    	printThread3.setName("Thread 3");
    	
    	PrintThread printThread4 = (PrintThread) ctx.getBean("printThread");
    	printThread4.setName("Thread 4");
    	
    	PrintThread printThread5 = (PrintThread) ctx.getBean("printThread");
    	printThread5.setName("Thread 5");
    	
    	printThread1.start();
    	printThread2.start();
    	printThread3.start();
    	printThread4.start();
    	printThread5.start();
    	
    }
}

Output – The order will be vary each time, this is thread :)


Thread 3 is running
Thread 2 is running
Thread 1 is running
Thread 5 is running
Thread 4 is running
Thread 2 is running
Thread 4 is running
Thread 5 is running
Thread 3 is running
Thread 1 is running

2. Spring Thread Pool + Spring non-managed bean example

Uses Spring’s ThreadPoolTaskExecutor to create a thread pool. The executing thread is not necessary managed by Spring container.

PrintThread.java – This thread is not managed by Spring, NO @Component

package com.mkyong.thread;

public class PrintTask implements Runnable{

	String name;
	
	public PrintTask(String name){
		this.name = name;
	}
	
	@Override
	public void run() {
		
		System.out.println(name + " is running");
		
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		
		System.out.println(name + " is running");
	}

}
Spring-Config.xml – ThreadPoolTaskExecutor in XML file

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context-3.1.xsd">

	<bean id="taskExecutor"
		class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
		<property name="corePoolSize" value="5" />
		<property name="maxPoolSize" value="10" />
		<property name="WaitForTasksToCompleteOnShutdown" value="true" />
	</bean>

</beans>
App.java

package com.mkyong;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import com.mkyong.thread.PrintTask;

public class App {
  public static void main(String[] args) {

    ApplicationContext context = new ClassPathXmlApplicationContext("Spring-Config.xml");
    ThreadPoolTaskExecutor taskExecutor = (ThreadPoolTaskExecutor) context.getBean("taskExecutor");
    taskExecutor.execute(new PrintTask("Thread 1"));
    taskExecutor.execute(new PrintTask("Thread 2"));
    taskExecutor.execute(new PrintTask("Thread 3"));
    taskExecutor.execute(new PrintTask("Thread 4"));
    taskExecutor.execute(new PrintTask("Thread 5"));

	//check active thread, if zero then shut down the thread pool
	for (;;) {
		int count = taskExecutor.getActiveCount();
		System.out.println("Active Threads : " + count);
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		if (count == 0) {
			taskExecutor.shutdown();
			break;
		}
	}

    }
}

Output – The order will be vary each time.


Thread 1 is running
Thread 2 is running
Thread 3 is running
Thread 4 is running
Active Threads : 4
Thread 5 is running
Active Threads : 5
Active Threads : 5
Active Threads : 5
Active Threads : 5
Thread 2 is running
Thread 1 is running
Thread 3 is running
Thread 4 is running
Thread 5 is running
Active Threads : 0

3. Spring Thread Pool + Spring managed bean example

This example is using ThreadPoolTaskExecutor again, and declares the thread as Spring managed bean via @Component.

The below PrintTask2 is Spring managed bean, you can @Autowired any required beans easily.

PrintTask2.java

package com.mkyong.thread;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("prototype")
public class PrintTask2 implements Runnable{

	String name;
	
	public void setName(String name){
		this.name = name;
	}
	
	@Override
	public void run() {
		
		System.out.println(name + " is running");
		
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		
		System.out.println(name + " is running");

	}

}
AppConfig.java – ThreadPoolTaskExecutor in Spring configuration file

package com.mkyong.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

@Configuration
@ComponentScan(basePackages = "com.mkyong.thread")
public class AppConfig {

	@Bean
	public ThreadPoolTaskExecutor taskExecutor() {
		ThreadPoolTaskExecutor pool = new ThreadPoolTaskExecutor();
		pool.setCorePoolSize(5);
		pool.setMaxPoolSize(10);
		pool.setWaitForTasksToCompleteOnShutdown(true);
		return pool;
	}

}
App.java

package com.mkyong;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import com.mkyong.config.AppConfig;
import com.mkyong.thread.PrintTask2;

public class App {
  public static void main(String[] args) {
		
    ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
    ThreadPoolTaskExecutor taskExecutor = (ThreadPoolTaskExecutor) context.getBean("taskExecutor");

    PrintTask2 printTask1 = (PrintTask2) context.getBean("printTask2");
    printTask1.setName("Thread 1");
    taskExecutor.execute(printTask1);

    PrintTask2 printTask2 = (PrintTask2) context.getBean("printTask2");
    printTask2.setName("Thread 2");
    taskExecutor.execute(printTask2);

    PrintTask2 printTask3 = (PrintTask2) context.getBean("printTask2");
    printTask3.setName("Thread 3");
    taskExecutor.execute(printTask3);

	for (;;) {
		int count = taskExecutor.getActiveCount();
		System.out.println("Active Threads : " + count);
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		if (count == 0) {
			taskExecutor.shutdown();
			break;
		}
	}
		 
   }
}

Output – The order will be vary each time.


Thread 1 is running
Thread 2 is running
Thread 3 is running
Active Threads : 2
Active Threads : 3
Active Threads : 3
Active Threads : 3
Active Threads : 3
Thread 1 is running
Thread 3 is running
Thread 2 is running
Active Threads : 0

Love your comment to improve above program.

Download Source Code

Download it – Spring-Thread-Example.zip (22 KB)

References

  1. Spring scheduling references
  2. ThreadPoolTaskExecutor JavaDoc
  3. Declares bean in Spring Configuration file
  4. How can I shut down the Spring task executor/scheduler pools
  5. Spring Concurrency example

About the Author

author image
mkyong
Founder of Mkyong.com, love Java and open source stuff. Follow him on Twitter, or befriend him on Facebook or Google Plus. If you like my tutorials, consider make a donation to these charities.

Comments

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giorgoch
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giorgoch

what if i want to control each Thread when to start and choose which printTask should start?I mean iwant to make each thread run as desired and if it start a task the next thread must not start.How can i do it?

revathi
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revathi

Spring Thread Pool + Spring non-managed bean example…..the run() is not calling after taskexecutor.execute method

Spencer
Guest
Spencer

Great example! Might I ask why you extend Thread instead of implementing Runnable?

Sting Ray
Guest
Sting Ray

Thx great example. When using “Spring Thread Pool + Spring managed bean example” one might need to implement factory pattern for task to be inside the spring context. See -> http://stackoverflow.com/questions/29495353/get-new-instance-of-a-spring-bean

Cheers

Zeus
Guest
Zeus

No words! simply awesome! Thanks for the great tutorial. The prototype bean in the task executor is a deal breaker for me.

Ashish Gupta
Guest
Ashish Gupta

How to manage transaction inside Thread. I have tried to use taskExecutor but getting the exception in my DAO class “org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread ”

P

senthil
Guest
senthil

Is there any way to stop the particular thread using the ID/Name?

Rafael Vieira
Guest
Rafael Vieira

Very nice examples, helped a lot.

I have a question: it all works fine when just reading from de database. When I try to write to it, I get a “no transaction is in progress” exception. Method is public and in another @Service bean (not in the Runnable one), annotated with @Transactional.

Does anybody has faced a similar problem?

tony
Guest
tony

GOOD~!~!

Sears Auto printable discount coupons
Guest
Sears Auto printable discount coupons

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Anand
Guest
Anand

Hi All,
I have placed few Java Multi threading questions with complete java code. Please take a look one who need – http://www.javadiscover.blogspot.com/search/label/Threads

Thanks
Anand

Naveen
Guest
Naveen

java.lang.NoClassDefFoundError: and
Caused by: java.lang.ClassNotFoundException: and
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Exception in thread “main”

Kindly provide a solution for this., when i run a java application testcase. I face this issue. Please provide me a solution. Thanks in advance. I see all the necessary jars imported to the workspace and i am using eclipse helios.

sagar
Guest
sagar
Please can you post some core Java multi-threading examples, its too confusing.
Abdennour
Guest
Abdennour

Thank You . Keep Going!

we can also use the new scope directly which is thread scope :
http://abdennour-insat.blogspot.com/2012/11/spring-bean-thread-scope.html