private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vmmigration.v1.AvailableUpdates,
            com.google.cloud.vmmigration.v1.AvailableUpdates.Builder,
            com.google.cloud.vmmigration.v1.AvailableUpdatesOrBuilder>
        getAvailableVersionsFieldBuilder() {
      if (availableVersionsBuilder_ == null) {
        availableVersionsBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vmmigration.v1.AvailableUpdates,
                com.google.cloud.vmmigration.v1.AvailableUpdates.Builder,
                com.google.cloud.vmmigration.v1.AvailableUpdatesOrBuilder>(
                getAvailableVersions(), getParentForChildren(), isClean());
        availableVersions_ = null;
      }
      return availableVersionsBuilder_;
    }
<pre>
Output only. The available versions for updating this appliance.
</pre>

<code>
.google.cloud.vmmigration.v1.AvailableUpdates available_versions = 15 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/DatacenterConnector.java