spring boot maven plugin stop goal

Question

Spring boot maven plugin stop goal fails to stop the application and leaves the application process hanging (and I and cannot start another process using the same port). This is the plugin configuration I have:

        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <version>1.5.6.RELEASE</version>
            <configuration>
                <jvmArguments>-DCONFIG_ENVIRONMENT=functionaltest</jvmArguments>
                <mainClass>...</mainClass>
                <fork>true</fork>
            </configuration>
            <executions>
                <execution>
                    <id>start-service</id>
                    <phase>pre-integration-test</phase>
                    <goals>
                        <goal>start</goal>
                    </goals>
                </execution>
                <execution>
                    <id>stop-service</id>
                    <phase>post-integration-test</phase>
                    <goals>
                        <goal>stop</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

I can't find any reference to a bug causing this behaviour. Am I using the plugin in a way it was not meant to be used maybe?

Answer 1

I found the problem: the spring boot application (in its main thread) starts a new thread that prevents the jvm from shutting down. Changing the "child" thread to be a daemon thread solved the issue.

Code with issue

        private ExecutorService executorService = Executors.newSingleThreadExecutor(r -> {
            Thread t = new Thread(r);
            return t;
        });

Code that solved the issue

        private ExecutorService executorService = Executors.newSingleThreadExecutor(r -> {
            Thread t = new Thread(r);
            t.setDaemon(true);
            return t;
        });

Check out this SO question for more details about daemon thrreads in Java.