code: public boolean collectionExists(final String collectionName) {
          Set<String> collectionNames = getCollectionNames();
          for (final String name : collectionNames) {
              if (name.equalsIgnoreCase(collectionName)) {
                  return true;
              }
          }
          return false;
      }
docs: Checks to see if a collection with a given name exists on a server.
  
  @param collectionName a name of the collection to test for existence
  @return {@code false} if no collection by that name exists, {@code true} if a match to an existing collection was found
  @throws MongoException if the operation failed