public java.lang.String getAppId() {
      java.lang.Object ref = appId_;
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        appId_ = s;
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Required. The App ID is supplied as an HTTP parameter. Unlike internal
usage of App ID, it does not include a region prefix. Rather, the App ID
represents the Project ID against which to make the request.
</pre>

<code>string app_id = 1 [(.google.api.field_behavior) = REQUIRED];</code>

@return The appId.
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/UploadQueueYamlRequest.java