Validating connections in a pool in JBoss application server for MySQL

MySQL connections in a pool times out after a long period of inactivity [I believe 8 hours is the time period by default.] Hence the connections in the pool become stale and this results in exceptions like java.sql.SQLException: Communication link failure.(The same scenario can also be
simulated by bringing JBoss up when MySQL is up and running and then restarting MySQL server.) To avoid this we have to instruct JBoss to validate a connection by issuing a test SQL.

Option 1 and the preferred way to do it is to place the following in the datasource configuration file for JBoss

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE datasources
    PUBLIC "-//JBoss//DTD JBOSS JCA Config 1.5//EN"
    "http://www.jboss.org/j2ee/dtd/jboss-ds_1_5.dtd">

<datasources>
    <local-tx-datasource>
        <jndi-name>TestDB</jndi-name>
        <connection-url>jdbc:mysql://localhost:3306/seam</connection-url>

        <driver-class>com.mysql.jdbc.Driver</driver-class>
        <user-name>root</user-name>
        <password>password</password>
        <min-pool-size>4</min-pool-size>
        <max-pool-size>20</max-pool-size>
        <idle-timeout-minutes>10</idle-timeout-minutes>
        <exception-sorter-class-name>
    com.mysql.jdbc.integration.jboss.ExtendedMysqlExceptionSorter
        </exception-sorter-class-name>
        <valid-connection-checker-class-name>
    com.mysql.jdbc.integration.jboss.MysqlValidConnectionChecker
        </valid-connection-checker-class-name>
        <background-validation>true</background-validation>
        <background-validation-minutes>10</background-validation-minutes>
        <metadata>
            <type-mapping>mySQL</type-mapping>
        </metadata>

    </local-tx-datasource>

</datasources>

Option 2 - We can also calidate the connection by using the following 

   <check-valid-connection-sql>select 1</check-valid-connection-sql>
  <new-connection-sql>select 1</new-connection-sql> 

But JBoss documentation suggests that Option 1 is the preferred way.