code: public ServiceFuture<Boolean> checkNameExistsAsync(String accountName, final ServiceCallback<Boolean> serviceCallback) {
          return ServiceFuture.fromResponse(checkNameExistsWithServiceResponseAsync(accountName), serviceCallback);
      }
docs: Checks that the Azure Cosmos DB account name already exists. A valid account name may contain only lowercase letters, numbers, and the '-' character, and must be between 3 and 50 characters.
  
  @param accountName Cosmos DB database account name.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object