code: public Observable<ServiceResponse<BackupShortTermRetentionPolicyInner>> createOrUpdateWithServiceResponseAsync(String resourceGroupName, String serverName, String databaseName) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (serverName == null) {
              throw new IllegalArgumentException("Parameter serverName is required and cannot be null.");
          }
          if (databaseName == null) {
              throw new IllegalArgumentException("Parameter databaseName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          final String policyName = "default";
          final Integer retentionDays = null;
          BackupShortTermRetentionPolicyInner parameters = new BackupShortTermRetentionPolicyInner();
          parameters.withRetentionDays(null);
          Observable<Response<ResponseBody>> observable = service.createOrUpdate(resourceGroupName, serverName, databaseName, policyName, this.client.subscriptionId(), this.client.apiVersion(), this.client.acceptLanguage(), parameters, this.client.userAgent());
          return client.getAzureClient().getPutOrPatchResultAsync(observable, new TypeToken<BackupShortTermRetentionPolicyInner>() { }.getType());
      }
docs: Updates a database's short term retention policy.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param serverName The name of the server.
  @param databaseName The name of the database.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request