code: public static synchronized void close() {
          if (mongoEmbeddedLibrary != null) {
              try {
                  mongoEmbeddedLibrary.close();
              } catch (Exception e) {
                  throw new MongoClientEmbeddedException(format("Could not close the mongo embedded library.%n"
                          + "Please ensure that any MongoClient instances have been closed first.%n"
                          + "Server error message: %s", e.getMessage()), e);
              }
              mongoEmbeddedLibrary = null;
  
          }
      }
docs: Closes down the mongod library