How do I use the Android Library in Unity?

Hi,Can someone point me on how to use android library project with unity..?I created a library project in eclipse.I need to use it as a Android Library Project not just the jar file in the plugin/Android folder.The folder structure will be like

--Plugins

    --Android

      --MyLibraryProject

                    --Src

                    --res

                    --bin

                    --libs

Now how can I access the Java class if my library package name is com.company.product and the class activity name is MyActivity

It tried this

 private static AndroidJavaClass Javaclass = new AndroidJavaClass("com.company.Product.MyActivity");
 private static AndroidJavaObject JavaObj = Javaclass.GetStatic<AndroidJavaObject>("_activity");
 
 
 //where the _activity reference is got from bundle creator in the Libraryproject java file
 
         public static Activity _activity;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) 
     {
            //Get the current activity        
        _activity = Activity;
     }

but this gives me the java class and object as null

Any help would be appreciated.