default Container getContainerByName(String accountName, String containerName) throws AccountServiceException {
    Account account = getAccountByName(accountName);
    return account != null ? account.getContainerByName(containerName) : null;
  }
Get an existing container from a given account.
@param accountName the name of account which container belongs to.
@param containerName the name of container to get.
@return the requested {@link Container} object or null if not present.
@throws AccountServiceException if exception occurs when getting container.
ambry-api/src/main/java/com/github/ambry/account/AccountService.java