java ee mongo injection not working

This is my MongoClient Class that I want to inject into my Java EE Application. package org.sam.test;

import javax.annotation.PostConstruct;
import javax.ejb.ConcurrencyManagement;
import javax.ejb.ConcurrencyManagementType;
import javax.ejb.Lock;
import javax.ejb.LockType;
import javax.ejb.Singleton;
import javax.ejb.Startup;
import javax.inject.Named;
import javax.inject.Inject;
import com.mongodb.MongoClient;

@Singleton
@ConcurrencyManagement(ConcurrencyManagementType.CONTAINER)
public class MongoConnectServer {

private MongoClient mongoClient = null;

public MongoConnectServer() {
    String mongoIpAddress = "127.0.0.1";
    Integer mongoPort = 27017;
    try {
        mongoClient = new MongoClient(mongoIpAddress, mongoPort);
    } catch (Exception e) {
        e.printStackTrace();
    }   
}

@Lock(LockType.READ)
public MongoClient getMongoClient(){    
    System.out.println(mongoClient);
    return mongoClient;
}

public void setMongoClient(MongoClient mongoClient) {
    this.mongoClient = mongoClient;
}

@PostConstruct
public void init() {
    String mongoIpAddress = "127.0.0.1";
    Integer mongoPort = 27017;
    try {
        mongoClient = new MongoClient(mongoIpAddress, mongoPort);
    } catch (Exception e) {
        e.printStackTrace();
    }       
}   

}

Here is the main application, for some reason the mongoserver is giving me a null pointer exception and cannot figure out why it doesn't work, when I create an instance of MongoServer where the constructor passes the values then it works as shown in the lines below, any ideas how can I inject the Mongo Server, the post construct from MongoConnectServer to pass mongoclient doesn't seem to initialise the value, I am trying to avoid using new in the bean and want to inject the mongo class:

@Stateless
public class Test {

@EJB
static MongoConnectServer mongoserver;

public static void main(String[] args) {
/* Uncommenting this line below works */
//MongoConnectServer mongoserver = new MongoConnectServer();

 System.out.println("App Start");
 System.out.println(mongoserver);
 MongoClient mongoClient = mongoserver.getMongoClient();

    DB db = mongoClient.getDB("mydb");
    DBCollection coll = db.getCollection("testCollection");
    System.out.println(coll);

    BasicDBObject doc = new BasicDBObject("name", "MongoDB")
    .append("type", "database")
    .append("count", 1)
    .append("info", new BasicDBObject("x", 203).append("y", 102));
    coll.insert(doc);


    DBObject myDoc = coll.findOne();
    System.out.println(myDoc);  

 }
}

Thanks for any responses