Not able to inject @Service and @Contract dependency in my resource class

Question

On base of the guide from this blog, Roll your own Auto Discovery with Jersey and HK2 , I have the follow resource POJO :

@Path("Test")
public class TestResource {
    @Inject
    private TestService service;
    @GET
    @Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
    public Set<Test> getTests() {
        return service.getAllTests();
    }
}

The TestService :

@Contract
public interface TestService {
    public Set<Test> getAllTests();
}

The TestServiceImpl

@Service
public class TestServiceImpl implements TestService {

    @Override
    public Set<Test> getAllTests() {
        Set<Test> tests = new HashSet<>();
        Test c = new Test();
        c.setName("test");
        tests.add(c);
        return tests;
    }
}

The Jersey dependency in pom.xml is of version 2.25.1

   <dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey</groupId>
            <artifactId>jersey-bom</artifactId>
            <version>${jersey.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
<dependency>
<groupId>javax.ws.rs</groupId>
<artifactId>javax.ws.rs-api</artifactId>
<version>2.0</version>
</dependency>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet-core</artifactId>
        <!-- use the following artifactId if you don't need servlet 2.x compatibility -->
        <!-- artifactId>jersey-container-servlet</artifactId -->
    </dependency>
     <dependency>
        <groupId>org.glassfish.jersey.bundles</groupId>
        <artifactId>jaxrs-ri</artifactId>
        </dependency>
     <dependency>
         <groupId>org.glassfish.jersey.media</groupId>
         <artifactId>jersey-media-json-jackson</artifactId>
     </dependency>
     <dependency>
         <groupId>org.glassfish.hk2</groupId>
         <artifactId>hk2</artifactId>
         <version>2.5.0-b36</version>
     </dependency>

In order to make Jersey scan the @Service and @Contract classes automatically , I used the inhabitant-generator plugin with version 2.5.0-b36:

<plugin>
  <groupId>org.glassfish.hk2</groupId>
  <artifactId>hk2-inhabitant-generator</artifactId>
  <version>2.5.0-b36</version>
  <executions>
    <execution>
      <goals>
        <goal>generate-inhabitants</goal>
      </goals>
    </execution>
  </executions>
</plugin>

There is the corresponding Feature implementation:

public class AutoServiceDiscovery implements Feature {

@Override
public boolean configure(FeatureContext context) {
    ServiceLocator locator = ServiceLocatorProvider.getServiceLocator(context);
    DynamicConfigurationService dcs = locator.getService(DynamicConfigurationService.class);
    Populator populator = dcs.getPopulator();
    try {
        populator.populate(new ClasspathDescriptorFileFinder(this.getClass().getClassLoader()),
                new DuplicatePostProcessor());
    } catch (IOException | MultiException ex) {
        Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
    }
    return true;
}

}

And it is indeeded registered through my ResourceConfig class:

@ApplicationPath("/*")
public class ApplicationConfig extends ResourceConfig {
    public ApplicationConfig() {
        packages("resources");
        register(new AutoServiceDiscovery());
}

} However, I send request to the /test , got the following error:

MultiException has 3 exceptions.  They are:
1. org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for 
injection at SystemInjecteeImpl(requiredType=TestService,parent=TestResource,qualifiers=
{},position=-1,optional=false,self=false,unqualified=null,1947073589)
2. java.lang.IllegalArgumentException: While attempting to resolve the dependencies of 
rx.practice.ee.jaxrs.resources.TestResource errors were found
3. java.lang.IllegalStateException: Unable to perform operation: resolve on 
rx.practice.ee.jaxrs.resources.TestResource

org.jvnet.hk2.internal.Collector.throwIfErrors(Collector.java:89)
org.jvnet.hk2.internal.ClazzCreator.resolveAllDependencies(ClazzCreator.java:250)
org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:358)
org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:487)
org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:162)
...

Question: Anyone knows why the @Service class cannot be injected? I am using Tomcat server

Answer 1

After a couple of days research on the source code of inhabitat-generator , I figured out that in case of web application package, war , the locator file is not generated in META-INF/hk2-locator as demonstracted in the HK2 Inhabitant Generator office site in case of using jar as deployment package. The source code of AbstractInhabitantsGeneratorMojo.java told that in case of war , locator files are generated in hk2-locator , and this is not mentioned in the HK2 Inhabitant Generator office site .

However, when constructing the ClasspathDescriptorFileFinder without the directory names argument in the bootstrap class, AutoServiceDiscovery , it is only compatible with jar as deployment package, meaning it is only finding files in META-INF/hk2-locator .

So the better solution would be not to use inhabitant-generator plugin but the metadata-generator dependency, which is an annotation processor at compile time and, it is proved out-of-the-box .

If someone is persistent to using this plugin, he/she could create his/her own ClasspathDescriptorFileFinder so that it is able to find locator files from hk2-locator

Last but not least, I also tried to use the inhabitants-generator plugin's options to generate the locator files in hk2-locator , but this seems to be next to impossible as well