private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.tasks.v2beta2.AppEngineHttpTarget,
            com.google.cloud.tasks.v2beta2.AppEngineHttpTarget.Builder,
            com.google.cloud.tasks.v2beta2.AppEngineHttpTargetOrBuilder>
        getAppEngineHttpTargetFieldBuilder() {
      if (appEngineHttpTargetBuilder_ == null) {
        if (!(targetTypeCase_ == 3)) {
          targetType_ = com.google.cloud.tasks.v2beta2.AppEngineHttpTarget.getDefaultInstance();
        }
        appEngineHttpTargetBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.tasks.v2beta2.AppEngineHttpTarget,
                com.google.cloud.tasks.v2beta2.AppEngineHttpTarget.Builder,
                com.google.cloud.tasks.v2beta2.AppEngineHttpTargetOrBuilder>(
                (com.google.cloud.tasks.v2beta2.AppEngineHttpTarget) targetType_,
                getParentForChildren(),
                isClean());
        targetType_ = null;
      }
      targetTypeCase_ = 3;
      onChanged();
      return appEngineHttpTargetBuilder_;
    }
<pre>
App Engine HTTP target.

An App Engine queue is a queue that has an
[AppEngineHttpTarget][google.cloud.tasks.v2beta2.AppEngineHttpTarget].
</pre>

<code>.google.cloud.tasks.v2beta2.AppEngineHttpTarget app_engine_http_target = 3;</code>
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/Queue.java