private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults,
            com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults.Builder,
            com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaultsOrBuilder>
        getComputeEngineTargetDefaultsFieldBuilder() {
      if (computeEngineTargetDefaultsBuilder_ == null) {
        if (!(targetVmDefaultsCase_ == 26)) {
          targetVmDefaults_ =
              com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults.getDefaultInstance();
        }
        computeEngineTargetDefaultsBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults,
                com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults.Builder,
                com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaultsOrBuilder>(
                (com.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults) targetVmDefaults_,
                getParentForChildren(),
                isClean());
        targetVmDefaults_ = null;
      }
      targetVmDefaultsCase_ = 26;
      onChanged();
      return computeEngineTargetDefaultsBuilder_;
    }
<pre>
Details of the target VM in Compute Engine.
</pre>

<code>
.google.cloud.vmmigration.v1.ComputeEngineTargetDefaults compute_engine_target_defaults = 26;
</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/MigratingVm.java