public java.lang.String getRequestId() {
      java.lang.Object ref = requestId_;
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        requestId_ = s;
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Optional. An optional request ID to identify requests. Specify a unique
request ID in case you need to retry your request. Requests with same
`request_id` will be ignored for at least 60 minutes since the first
request. The request ID must be a valid UUID with the exception that zero
UUID is not supported (00000000-0000-0000-0000-000000000000).
</pre>

<code>string request_id = 3 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The requestId.
java-storagebatchoperations/proto-google-cloud-storagebatchoperations-v1/src/main/java/com/google/cloud/storagebatchoperations/v1/CancelJobRequest.java