private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vmmigration.v1.AwsSourceVmDetails,
            com.google.cloud.vmmigration.v1.AwsSourceVmDetails.Builder,
            com.google.cloud.vmmigration.v1.AwsSourceVmDetailsOrBuilder>
        getAwsSourceVmDetailsFieldBuilder() {
      if (awsSourceVmDetailsBuilder_ == null) {
        if (!(sourceVmDetailsCase_ == 29)) {
          sourceVmDetails_ =
              com.google.cloud.vmmigration.v1.AwsSourceVmDetails.getDefaultInstance();
        }
        awsSourceVmDetailsBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vmmigration.v1.AwsSourceVmDetails,
                com.google.cloud.vmmigration.v1.AwsSourceVmDetails.Builder,
                com.google.cloud.vmmigration.v1.AwsSourceVmDetailsOrBuilder>(
                (com.google.cloud.vmmigration.v1.AwsSourceVmDetails) sourceVmDetails_,
                getParentForChildren(),
                isClean());
        sourceVmDetails_ = null;
      }
      sourceVmDetailsCase_ = 29;
      onChanged();
      return awsSourceVmDetailsBuilder_;
    }
<pre>
Output only. Details of the VM from an AWS source.
</pre>

<code>
.google.cloud.vmmigration.v1.AwsSourceVmDetails aws_source_vm_details = 29 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/MigratingVm.java