SpringBootTest does not work with Java 10/modules

[keirlawson]

I attempted to port the Spring web testing example at https://github.com/spring-guides/gs-testing-web to Java 10 and modules, however I find when running my tests via Maven that the @SpringBootTest annotation is no longer able to locate my application class despite the code working previously before modularisation.I receive the following error when running mvn test

java.lang.IllegalStateException: Unable to find a @SpringBootConfiguration, you need to use @ContextConfiguration or @SpringBootTest(classes=...) with your test

Adding the application class explicitly as this message suggests then results in

java.lang.reflect.InaccessibleObjectException: Unable to make field private static java.lang.Object hello.Application$$EnhancerBySpringCGLIB$$d7dfca41.CGLIB$CALLBACK_FILTER accessible: module gs.testing.web does not "opens hello" to unnamed module @2fc6f97f

The changes I made to the initial repo can be viewed here: spring-guides/gs-testing-web@master...keirlawson:j10_modules

[wilkinsona]

Thanks for the report.

Being unable to find @SpringBootConfiguration is indicative of classpath scanning not working correctly. Specifying the application class explicitly means that scanning isn't used.

The second problem is trying to point out that your module-info is incorrect and that you need to add opens hello to it:

module gs.testing.web {
    requires spring.web;
    requires spring.boot;
    requires spring.boot.autoconfigure;
    requires spring.context;
    opens hello;
}

With that change in place, SmokeTest fails as the controller cannot be injected:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'hello.SmokeTest': Unsatisfied dependency expressed through field 'controller'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'hello.HomeController' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:401) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118) ~[spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) ~[spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:44) ~[spring-boot-test-autoconfigure-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246) ~[spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) [spring-test-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:365) [surefire-junit4-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:273) [surefire-junit4-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238) [surefire-junit4-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:159) [surefire-junit4-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:383) [surefire-booter-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:344) [surefire-booter-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:125) [surefire-booter-2.22.0.jar:2.22.0]
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:417) [surefire-booter-2.22.0.jar:2.22.0]
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'hello.HomeController' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1509) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 31 common frames omitted

As with the first problem, this is indicative of classpath scanning not working correctly. This can be confirmed by adding another test class:

package hello;

import java.util.Arrays;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

public class ScanningTest {

    @Test
    public void scanningTest() throws Exception {
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        System.out.println(Arrays.toString(resolver.getResources("classpath*:hello/**/*.class")));
    }

}

It produces the following output:

[file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/ApplicationTest.class], file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/HttpRequestTest.class], file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/ScanningTest.class], file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/SmokeTest.class], file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/WebLayerTest.class], file [/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes/hello/WebMockTest.class]]

Note that the only classes that have been found are in target/test-classes and those in target/classes have been missed.

The args that Surefire uses to launch the forked JVM are written to target/surefire. This file is usually deleted on exit but it preserved when running with -X. It has contents similar to the following:

--module-path
/Users/awilkinson/dev/temp/gs-testing-web/complete/target/classes:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot/2.0.3.RELEASE/spring-boot-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/2.0.3.RELEASE/spring-boot-autoconfigure-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-web/5.0.7.RELEASE/spring-web-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-context/5.0.7.RELEASE/spring-context-5.0.7.RELEASE.jar
--class-path
/Users/awilkinson/.m2/repository/org/apache/maven/surefire/surefire-booter/2.22.0/surefire-booter-2.22.0.jar:/Users/awilkinson/.m2/repository/org/apache/maven/surefire/surefire-api/2.22.0/surefire-api-2.22.0.jar:/Users/awilkinson/.m2/repository/org/apache/maven/surefire/surefire-logger-api/2.22.0/surefire-logger-api-2.22.0.jar:/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter-web/2.0.3.RELEASE/spring-boot-starter-web-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter/2.0.3.RELEASE/spring-boot-starter-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter-logging/2.0.3.RELEASE/spring-boot-starter-logging-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar:/Users/awilkinson/.m2/repository/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar:/Users/awilkinson/.m2/repository/org/apache/logging/log4j/log4j-to-slf4j/2.10.0/log4j-to-slf4j-2.10.0.jar:/Users/awilkinson/.m2/repository/org/apache/logging/log4j/log4j-api/2.10.0/log4j-api-2.10.0.jar:/Users/awilkinson/.m2/repository/org/slf4j/jul-to-slf4j/1.7.25/jul-to-slf4j-1.7.25.jar:/Users/awilkinson/.m2/repository/javax/annotation/javax.annotation-api/1.3.2/javax.annotation-api-1.3.2.jar:/Users/awilkinson/.m2/repository/org/yaml/snakeyaml/1.19/snakeyaml-1.19.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter-json/2.0.3.RELEASE/spring-boot-starter-json-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.9.6/jackson-databind-2.9.6.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.9.0/jackson-annotations-2.9.0.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.9.6/jackson-core-2.9.6.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.9.6/jackson-datatype-jdk8-2.9.6.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.9.6/jackson-datatype-jsr310-2.9.6.jar:/Users/awilkinson/.m2/repository/com/fasterxml/jackson/module/jackson-module-parameter-names/2.9.6/jackson-module-parameter-names-2.9.6.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.0.3.RELEASE/spring-boot-starter-tomcat-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/8.5.31/tomcat-embed-core-8.5.31.jar:/Users/awilkinson/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/8.5.31/tomcat-embed-el-8.5.31.jar:/Users/awilkinson/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/8.5.31/tomcat-embed-websocket-8.5.31.jar:/Users/awilkinson/.m2/repository/org/hibernate/validator/hibernate-validator/6.0.10.Final/hibernate-validator-6.0.10.Final.jar:/Users/awilkinson/.m2/repository/javax/validation/validation-api/2.0.1.Final/validation-api-2.0.1.Final.jar:/Users/awilkinson/.m2/repository/org/jboss/logging/jboss-logging/3.3.2.Final/jboss-logging-3.3.2.Final.jar:/Users/awilkinson/.m2/repository/com/fasterxml/classmate/1.3.4/classmate-1.3.4.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-beans/5.0.7.RELEASE/spring-beans-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-webmvc/5.0.7.RELEASE/spring-webmvc-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-aop/5.0.7.RELEASE/spring-aop-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-expression/5.0.7.RELEASE/spring-expression-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-starter-test/2.0.3.RELEASE/spring-boot-starter-test-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-test/2.0.3.RELEASE/spring-boot-test-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/boot/spring-boot-test-autoconfigure/2.0.3.RELEASE/spring-boot-test-autoconfigure-2.0.3.RELEASE.jar:/Users/awilkinson/.m2/repository/com/jayway/jsonpath/json-path/2.4.0/json-path-2.4.0.jar:/Users/awilkinson/.m2/repository/net/minidev/json-smart/2.3/json-smart-2.3.jar:/Users/awilkinson/.m2/repository/net/minidev/accessors-smart/1.2/accessors-smart-1.2.jar:/Users/awilkinson/.m2/repository/org/ow2/asm/asm/5.0.4/asm-5.0.4.jar:/Users/awilkinson/.m2/repository/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar:/Users/awilkinson/.m2/repository/junit/junit/4.12/junit-4.12.jar:/Users/awilkinson/.m2/repository/org/assertj/assertj-core/3.9.1/assertj-core-3.9.1.jar:/Users/awilkinson/.m2/repository/org/mockito/mockito-core/2.15.0/mockito-core-2.15.0.jar:/Users/awilkinson/.m2/repository/net/bytebuddy/byte-buddy/1.7.11/byte-buddy-1.7.11.jar:/Users/awilkinson/.m2/repository/net/bytebuddy/byte-buddy-agent/1.7.11/byte-buddy-agent-1.7.11.jar:/Users/awilkinson/.m2/repository/org/objenesis/objenesis/2.6/objenesis-2.6.jar:/Users/awilkinson/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar:/Users/awilkinson/.m2/repository/org/hamcrest/hamcrest-library/1.3/hamcrest-library-1.3.jar:/Users/awilkinson/.m2/repository/org/skyscreamer/jsonassert/1.5.0/jsonassert-1.5.0.jar:/Users/awilkinson/.m2/repository/com/vaadin/external/google/android-json/0.0.20131108.vaadin1/android-json-0.0.20131108.vaadin1.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-core/5.0.7.RELEASE/spring-core-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-jcl/5.0.7.RELEASE/spring-jcl-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/springframework/spring-test/5.0.7.RELEASE/spring-test-5.0.7.RELEASE.jar:/Users/awilkinson/.m2/repository/org/xmlunit/xmlunit-core/2.5.1/xmlunit-core-2.5.1.jar:/Users/awilkinson/.m2/repository/org/apache/maven/surefire/surefire-junit4/2.22.0/surefire-junit4-2.22.0.jar
--patch-module
gs.testing.web=/Users/awilkinson/dev/temp/gs-testing-web/complete/target/test-classes
--add-exports
gs.testing.web/hello=ALL-UNNAMED
--add-modules
gs.testing.web
--add-reads
gs.testing.web=ALL-UNNAMED
org.apache.maven.surefire.booter.ForkedBooter

Note that target/classes is on the module path and thattarget/test-classes has been patched into gs.testing.web. As far as I can tell, Surefire has set things up properly which would suggest that this is a Spring Framework problem. I've opened https://jira.spring.io/browse/SPR-16977.

[keirlawson]

Thanks for getting back. I'm not clear why I should need to add opens hello for this test though, as the tests are in the same package they should not be crossing a module boundary?

[wilkinsona]

The tests may be in the same module but Spring Framework is not. From Spring Framework's reference documentation:

On JDK 9’s module path (Jigsaw), Spring’s classpath scanning generally works as expected. However, please make sure that your component classes are exported in your module-info descriptors; if you expect Spring to invoke non-public members of your classes, make sure that they are 'opened' (i.e. using an opens declaration instead of an exports declaration in your module-info descriptor).

[keirlawson]

Ok, that bit of documentation seems to imply that I need to export but not necessarily open said package then as so far as I can see there are no non-public members in use, yet when I just export it I get the same InaccessibleObjectException? Am I missing something here?

[wilkinsona]

Am I missing something here?

Yes, Spring Framework's use of CGLib to proxy your Application @Configuration class. CGLib adds non-public members which need to be accessible.