Cómo disparar consultas nativas de mongo usando java-mongo-driver solamente.

No Spring-Data o EclipseLink o Hibernate OGM,Solo usando java-mongo-driver

Consulta de muestra:

db.orders.aggregate([
   {
      $unwind: "$specs"
   },
   {
      $lookup:
         {
            from: "inventory",
            localField: "specs",
            foreignField: "size",
            as: "inventory_docs"
        }
   },
   {
      $match: { "inventory_docs": { $ne: [] } }
   }
])