DefaultManagedTaskScheduler
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This implementation implicitly initializes the underlying task scheduler via JNDI lookup. |
According to JSR-236 specification: The Java EE product provider (the application server) must bind a pre-configured, default ManagedScheduledExecutorService so that application components can find it under the JNDI name java:comp/DefaultManagedScheduledExecutorService.
Spring's DefaultManagedTaskScheduler internally initializes the underlying scheduler from this JNDI look up. The scheduler must be used as a bean otherwise this class will work as super class ConcurrentTaskScheduler.
Also this class is not strictly JSR-236 based; it can work with any regular ScheduledExecutorService that can be found in JNDI.
Example
In the following example we are not going to demonstrate implicit JNDI binding in a JEE server environment but instead we are going to bind "java:comp/DefaultManagedScheduledExecutorService" manually by using SimpleNamingContextBuilder.
package com.logicbig.example;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.concurrent.DefaultManagedTaskScheduler;
@Configuration
public class MyConfig {
@Bean
TaskScheduler taskScheduler() {
return new DefaultManagedTaskScheduler();
}
@Bean
MyBean myBean() {
return new MyBean();
}
}
package com.logicbig.example;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.TaskScheduler;
import java.time.LocalTime;
public class MyBean {
@Autowired
TaskScheduler taskScheduler;
public void runTask() {
taskScheduler.scheduleWithFixedDelay((Runnable) () -> {
System.out.println("running " + LocalTime.now());
}, 1000L);
}
}
package com.logicbig.example;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.mock.jndi.SimpleNamingContextBuilder;
import org.springframework.scheduling.concurrent.DefaultManagedTaskScheduler;
import javax.naming.NamingException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class DefaultManagedTaskSchedulerExample {
public static void main (String[] args) throws NamingException, InterruptedException {
//binding the scheduler manually,
// In JEE compliant server environment this will be
// provided by the server product
SimpleNamingContextBuilder b = new SimpleNamingContextBuilder();
b.bind("java:comp/DefaultManagedScheduledExecutorService",
Executors.newScheduledThreadPool(5));
b.activate();
//bootstrapping spring
ApplicationContext context =
new AnnotationConfigApplicationContext(MyConfig.class);
MyBean bean = context.getBean(MyBean.class);
bean.runTask();
//shutdown after 10 sec
Thread.sleep(10000);
DefaultManagedTaskScheduler scheduler = context.getBean(
DefaultManagedTaskScheduler.class);
Executor exec = scheduler.getConcurrentExecutor();
ExecutorService es = (ExecutorService) exec;
es.shutdownNow();
}
}
Outputrunning 16:31:29.728035500
running 16:31:30.731231800
running 16:31:31.732378100
running 16:31:32.733564200
running 16:31:33.734986400
running 16:31:34.736386
running 16:31:35.736719300
running 16:31:36.737566200
running 16:31:37.738595800
running 16:31:38.738936200
Example ProjectDependencies and Technologies Used: - spring-context 6.2.12 (Spring Context)
Version Compatibility: 4.0.0.RELEASE - 6.2.12 Version compatibilities of spring-context with this example: Versions in green have been tested.
- spring-test 4.0.0.RELEASE (Spring TestContext Framework)
- JDK 25
- Maven 3.9.11
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