Test never stops on Java 19 with config that includes @EnableScheduling and implementing the SchedulingConfigurer interface

[marinus-suniram]

The testcases never stop when including config that enables scheduling via @EnableScheduling and config that implements SchedulingConfigurer. Everything passes but it just hangs in the end.

This works perfectly on Java 17 and 18 but fails on Java 19 and 20.

I have tested this both on SpringBoot 3.0.7 and SpringBoot 2.7.12.

The config looks as follows

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;

import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

@Configuration
@EnableScheduling
public class ScheduleConfig implements SchedulingConfigurer {
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.setScheduler(taskExecutor());
    }

    /**
     * Works if this is not declared as a bean.
     */
    @Bean
    public Executor taskExecutor() {
        return Executors.newScheduledThreadPool(10);
    }

    @Scheduled(cron = "0 0 1 * * *")
    protected void schedule() {

    }
}

The testcase

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest(
        classes =
                {ScheduleConfig.class})
class TestIT {

    @Test
    void test() {
        //NOOP
    }
}

Maven pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SchedulerBug</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.7</version>
    </parent>

    <properties>
        <maven.compiler.source>19</maven.compiler.source>
        <maven.compiler.target>9</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

Console Output

07:55:02.902 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Neither @ContextConfiguration nor @ContextHierarchy found for test class [TestIT]: using SpringBootContextLoader
07:55:02.906 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader -- Could not detect default resource locations for test class [TestIT]: no resource found for suffixes {-context.xml, Context.groovy}.
07:55:02.924 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Using ContextCustomizers for test class [TestIT]: [ExcludeFilterContextCustomizer, DuplicateJsonObjectContextCustomizer, MockitoContextCustomizer, TestRestTemplateContextCustomizer, DisableObservabilityContextCustomizer, PropertyMappingContextCustomizer, Customizer]
07:55:02.993 [main] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Skipping candidate TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener] due to a missing dependency. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes and their required dependencies available. Offending class: [jakarta/servlet/ServletContext]
07:55:02.996 [main] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Skipping candidate TestExecutionListener [org.springframework.test.context.transaction.TransactionalTestExecutionListener] due to a missing dependency. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttributeSource]
07:55:02.997 [main] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Skipping candidate TestExecutionListener [org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener] due to a missing dependency. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttribute]
07:55:02.999 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Using TestExecutionListeners for test class [TestIT]: [DirtiesContextBeforeModesTestExecutionListener, ApplicationEventsTestExecutionListener, MockitoTestExecutionListener, DependencyInjectionTestExecutionListener, DirtiesContextTestExecutionListener, EventPublishingTestExecutionListener, ResetMocksTestExecutionListener, RestDocsTestExecutionListener, MockRestServiceServerResetTestExecutionListener, MockMvcPrintOnlyOnFailureTestExecutionListener, WebDriverTestExecutionListener, MockWebServiceServerTestExecutionListener]
07:55:03.000 [main] DEBUG org.springframework.test.context.support.AbstractDirtiesContextTestExecutionListener -- Before test class: class [TestIT], class annotated with @DirtiesContext [false] with mode [null]
07:55:03.012 [main] DEBUG org.springframework.test.context.support.DependencyInjectionTestExecutionListener -- Performing dependency injection for test class TestIT

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v3.0.7)

2023-06-03T07:55:03.247+02:00  INFO 819616 --- [           main] TestIT                                   : Starting TestIT using Java 19.0.2 with PID 819616 (started by pc in /home/pc/IdeaProjects/suniram/SchedulerBug)
2023-06-03T07:55:03.248+02:00  INFO 819616 --- [           main] TestIT                                   : No active profile set, falling back to 1 default profile: "default"
2023-06-03T07:55:03.401+02:00  INFO 819616 --- [           main] TestIT                                   : Started TestIT in 0.368 seconds (process running for 1.036)

[marinus-suniram]

Also failing on SpringBoot 3.1.0

[wilkinsona]

You aren't specifying how to shut down your custom Executor bean when the context closes. This results in the close() method (new in Java 19) being called which waits for queued tasks to complete. You can specify the method to use to shut down the executor using the destroyMethod attribute on the @Bean annotation. You probably want to use shutdown.

If you have any further questions, please follow up on Stack Overflow or Gitter. As mentioned in the guidelines for contributing, we prefer to use GitHub issues only for bugs and enhancements.

[marinus-suniram]

Thanks, I can confirm that adding the destroyMethod attribute fixes the issue.