public void setMasterUsername(String masterUsername) {
        this.masterUsername = masterUsername;
    }
<p>
The master user name of the DB instance.
</p>

@param masterUsername
       The master user name of the DB instance.
aws-java-sdk-securityhub/src/main/java/com/amazonaws/services/securityhub/model/AwsRdsDbInstanceDetails.java