Code samples for spring @Async annotation.

spring-all/src/main/java/org/baeldung/async/AsyncAnnotationExample.java

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+package org.baeldung.async;
+
+import java.util.concurrent.Future;
+
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.scheduling.annotation.AsyncResult;
+import org.springframework.stereotype.Component;
+
+@Component
+public class AsyncAnnotationExample {
+
+	@Async
+	public void asyncMethodWithVoidReturnType() {
+		System.out.println("Execute method asynchronously. "
+				+ Thread.currentThread().getName());
+	}
+
+	@Async
+	public Future<String> asyncMethodWithReturnType() {
+		System.out.println("Execute method asynchronously "
+				+ Thread.currentThread().getName());
+		try {
+			Thread.sleep(5000);
+			return new AsyncResult<String>("hello world !!!!");
+		} catch (final InterruptedException e) {
+
+		}
+
+		return null;
+	}
+
+	@Async("threadPoolTaskExecutor")
+	public void asyncMethodWithConfiguredExecutor() {
+		System.out
+				.println("Execute method asynchronously with configured executor"
+				+ Thread.currentThread().getName());
+	}
+
+	@Async
+	public void asyncMethodWithExceptions() throws Exception {
+		throw new Exception("Throw message from asynchronous method. ");
+	}
+}

spring-all/src/main/java/org/baeldung/async/CustomAsyncExceptionHandler.java

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+package org.baeldung.async;
+
+import java.lang.reflect.Method;
+
+import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
+
+public class CustomAsyncExceptionHandler implements
+AsyncUncaughtExceptionHandler {
+
+	@Override
+	public void handleUncaughtException(final Throwable throwable,
+			final Method method, final Object... obj) {
+		System.out.println("Exception message - " + throwable.getMessage());
+		System.out.println("Method name - " + method.getName());
+		for (final Object param : obj) {
+			System.out.println("Param - " + param);
+		}
+
+	}
+
+}

spring-all/src/main/java/org/baeldung/async/config/SpringAsyncConfig.java

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+package org.baeldung.async.config;
+
+import java.util.concurrent.Executor;
+
+import org.baeldung.async.CustomAsyncExceptionHandler;
+import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.task.SimpleAsyncTaskExecutor;
+import org.springframework.scheduling.annotation.AsyncConfigurer;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+@Configuration
+@EnableAsync()
+@ComponentScan("org.baeldung.async")
+public class SpringAsyncConfig implements AsyncConfigurer {
+
+	@Bean(name = "threadPoolTaskExecutor")
+	public Executor threadPoolTaskExecutor() {
+		return new ThreadPoolTaskExecutor();
+	}
+
+	@Override
+	public Executor getAsyncExecutor() {
+		return new SimpleAsyncTaskExecutor();
+	}
+
+	@Override
+	public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
+		return new CustomAsyncExceptionHandler();
+	}
+}

spring-all/src/main/resources/springAsync-config.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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"
+	xmlns:task="http://www.springframework.org/schema/task"
+	xsi:schemaLocation="http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.1.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
+		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd">
+	
+	<task:annotation-driven  executor="myExecutor" />
+	<task:executor id="myExecutor" pool-size="5"  />
+	
+	<bean id="asyncAnnotationExample" class="org.baeldung.async.AsyncAnnotationExample" />
+</beans>

spring-all/src/test/java/org/baeldung/async/AsyncAnnotationExampleTest.java

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+package org.baeldung.async;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+import org.baeldung.async.config.SpringAsyncConfig;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { SpringAsyncConfig.class }, loader = AnnotationConfigContextLoader.class)
+public class AsyncAnnotationExampleTest {
+
+	@Autowired
+	AsyncAnnotationExample asyncAnnotationExample;
+
+	@Test
+	public void testAsyncAnnotationForMethodsWithVoidReturnType() {
+		System.out.println("Start - invoking an asynchronous method. "
+				+ Thread.currentThread().getName());
+		asyncAnnotationExample.asyncMethodWithVoidReturnType();
+		System.out.println("End - invoking an asynchronous method. ");
+	}
+
+	@Test
+	public void testAsyncAnnotationForMethodsWithReturnType()
+			throws InterruptedException, ExecutionException {
+		System.out.println("Start - invoking an asynchronous method. "
+				+ Thread.currentThread().getName());
+		final Future<String> future = asyncAnnotationExample
+				.asyncMethodWithReturnType();
+
+		while (true) {
+			if (future.isDone()) {
+				System.out.println("Result from asynchronous process - "
+						+ future.get());
+				break;
+			}
+			System.out.println("Continue doing something else. ");
+			Thread.sleep(1000);
+		}
+	}
+
+	@Test
+	public void testAsyncAnnotationForMethodsWithConfiguredExecutor() {
+		System.out.println("Start - invoking an asynchronous method. ");
+		asyncAnnotationExample.asyncMethodWithConfiguredExecutor();
+		System.out.println("End - invoking an asynchronous method. ");
+	}
+
+	@Test
+	public void testAsyncAnnotationForMethodsWithException() throws Exception {
+		System.out.println("Start - invoking an asynchronous method. ");
+		asyncAnnotationExample.asyncMethodWithExceptions();
+		System.out.println("End - invoking an asynchronous method. ");
+	}
+}

spring-all/src/test/java/org/baeldung/async/AsyncWithXMLTest.java

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+package org.baeldung.async;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration("classpath:springAsync-config.xml")
+public class AsyncWithXMLTest {
+
+	@Autowired
+	AsyncAnnotationExample asyncAnnotationExample;
+
+	@Test
+	public void testAsyncAnnotationForMethodsWithVoidReturnType()
+			throws InterruptedException {
+		System.out.println("Start - invoking an asynchronous method. "
+				+ Thread.currentThread().getName());
+		asyncAnnotationExample.asyncMethodWithVoidReturnType();
+		Thread.sleep(2000);
+		System.out.println("End - invoking an asynchronous method. ");
+	}
+}