code: @BetaApi
    public final Operation updateUrlMap(
        ProjectGlobalUrlMapName urlMap, UrlMap urlMapResource, List<String> fieldMask) {
  
      UpdateUrlMapHttpRequest request =
          UpdateUrlMapHttpRequest.newBuilder()
              .setUrlMap(urlMap == null ? null : urlMap.toString())
              .setUrlMapResource(urlMapResource)
              .addAllFieldMask(fieldMask)
              .build();
      return updateUrlMap(request);
    }
docs: Updates the specified UrlMap resource with the data included in the request.
  
  <p>Sample code:
  
  <pre><code>
  try (UrlMapClient urlMapClient = UrlMapClient.create()) {
  ProjectGlobalUrlMapName urlMap = ProjectGlobalUrlMapName.of("[PROJECT]", "[URL_MAP]");
  UrlMap urlMapResource = UrlMap.newBuilder().build();
  List&lt;String&gt; fieldMask = new ArrayList&lt;&gt;();
  Operation response = urlMapClient.updateUrlMap(urlMap, urlMapResource, fieldMask);
  }
  </code></pre>
  
  @param urlMap Name of the UrlMap resource to update.
  @param urlMapResource A UrlMap resource. This resource defines the mapping from URL to the
  BackendService resource, based on the "longest-match" of the URL's host and path.
  @param fieldMask The fields that should be serialized (even if they have empty values). If the
  containing message object has a non-null fieldmask, then all the fields in the field mask
  (and only those fields in the field mask) will be serialized. If the containing object does
  not have a fieldmask, then only non-empty fields will be serialized.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails