When java.sql.SQLException is thrown, the root cause should be logged at the same time by MySQLValidConnectionChecker validation.
~~~
WARN [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) IJ030027: Destroying connection that is not valid, due to the following exception: com.mysql.jdbc.JDBC4Connection@5d0ae267: java.sql.SQLException: Ping failed: java.lang.reflect.InvocationTargetException
at org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLValidConnectionChecker.isValidConnection(MySQLValidConnectionChecker.java:93)
at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.isValidConnection(BaseWrapperManagedConnectionFactory.java:1272)
at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.getInvalidConnections(BaseWrapperManagedConnectionFactory.java:1085)
~~~
However, the current code is :
return new SQLException("Ping failed: " + e.toString());

so this should be modified by:
return new SQLException("Ping failed: " + e.toString(), e);

and logged message with root cause.