It is not clear if failsOnViolation serves a purpose as it was introduced in the ONAP parent repo:  oparent project, or a typo. Per  https://maven.apache.org/plugins/maven-checkstyle-plugin/check-mojo.html#failOnViolation.

Per the previous page failOnViolation is the only one in usage, some preliminary tests seem to indicate that failsOnViolation could be removed.