public String getMasterUserName() {
        return this.masterUserName;
    }
<p>
The master user's username, which is stored in the Amazon Elasticsearch Service domain's internal database.
</p>

@return The master user's username, which is stored in the Amazon Elasticsearch Service domain's internal
        database.
aws-java-sdk-elasticsearch/src/main/java/com/amazonaws/services/elasticsearch/model/MasterUserOptions.java