GlassFish 4.1.1: Unable to #Inject simple #Stateless in Java EE 7 JAX-RS App - glassfish

Question

I am using Glassfish 4.1.1 as my Java server. I am trying to #Inject a simple #Stateless bean in my JAX-RS class having #Path annotation. Here is the exception I am getting:
javax.servlet.ServletException: A MultiException has 1 exceptions. They are:
1. org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at SystemInjecteeImpl(requiredType=MongoCollectionStore,parent=DemoJaxrsApp,qualifiers={},position=-1,optional=false,self=false,unqualified=null,310751270)
Here is my JAX-RS config:
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;
#ApplicationPath("/rest")
public class JaxrsAppConfig extends Application {
}
This is how my JAX-RS resource class looks like:
#Path("/tn-collection")
#Produces(MediaType.APPLICATION_JSON)
#Consumes(MediaType.APPLICATION_JSON)
public class DemoJaxrsApp {
#Inject
MongoCollectionStore mongoCollectionStore;
#POST
public List<CollectionTO> getColl() {
return mongoCollectionStore.findAll();
}
}
I am using only 2 dependencies:
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.3.0</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.3.1</version>
</dependency>
It shouldn't be a problem with dependencies. I am not using any xml files (other than POM.xml and nb-configuration.xml, generated by Netbeans 8.1) as Java EE 7 need not have any config files. I don't know what might have going wrong.
Could anybody please help me out with this UnsatisfiedDependencyException problem?
UPDATE:
Here is my MongoCollectionStore Java class:
#Stateless
public class MongoCollectionStore {
public List<CollectionTO> findAll(MongoConfig mongoConfig) {
List<CollectionTO> tuples = new ArrayList<>();
Gson gson = new Gson();
MongoClient mongoClient = new MongoClient("127.0.0.1", 27017);
MongoDatabase mongoDB = mongoClient.getDatabase("Demo");
MongoCollection<Document> coll = mongoDB.getCollection("DemoCollection");
try(MongoCursor<Document> cursor = coll.find().iterator()) {
while (cursor.hasNext()) {
String jsonDoc = cursor.next().toJson();
CollectionTO tuple = gson.fromJson(jsonDoc, CollectionTO.class);
tuples.add(tuple);
}
}
return tuples;
}
}

Answer 1

I was looking through this problem on internet and found that a CDI bean can only be injected into another CDI bean. They both need to be managed by the container. So, I made my DemoJaxrsApp #RequestScoped, in order to make it a CDI bean.
For guys coming here from Google, Original (and more elaborate) answer can be found here:
Inject an EJB into JAX-RS (RESTful service)
One thing I still don't know is that when I #Injected a #Stateless resource inside my #RequestScoped class, was that resource an EJB? Or, was it a CDI bean? I guess, that's a different question altogether.