Gerald's Blog

If you get this errormessage on pinging your database from within the admin console....

"Operation 'pingConnectionPool' failed in 'resources' Config Mbean. Target exception message: Class name is wrong or classpath is not set for : com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource"

....then your jdbc-driver for mysql is missing!

get the jdbc-driver for MySQL here:
http://dev.mysql.com/downloads/connector/j/5.1.html

Move the file "mysql-connector-java-5.1.5-bin.jar" to the directory "%J2EE_HOME%\domains\domain1\lib\ext\"

(Re)Start the Application Server and create a new connection pool:
Common Tasks > Create New JDBC Connection Pool
I used following settings:
- Name: mysqlpool
- Resource Type: javax.sql.DataSource
- Database Vendor: mysql
[NEXT]

- Data Source Class Name: com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource

- serverName: 127.0.0.1 (just the localhost)
- port: 3306 (default port)
- user: (an existing user allowed to connect to your mysql db)
- password: (the users password)
- databaseName: (the name of the database you want to connect to)
[FINISH]

[PING]
Ping succeeded! Yay!

To use your new connection pool, just add a JDBC Resource and use its name in the persistence.xml for the DataSource like this:

<jta-data-source>%JNDI_NAME%</jta-data-source>

UPDATE:
Set only necessary options. If you get "No Database selected", try to delete the "url"-property or follow this advise:

When creating the connection pool DataSource properties, delete the “Url” property, and set the “URL” property. The URL may contain ?user=user&password=password, or you may leave them out and set “user” and “password” properties instead. These correspond to setURL(), setUser() and setPassword() on com.mysql.jdbc.jdbc2.optional.MysqlDataSource.

If you omit the URL property, you will get:

java.sql.SQLException: No database selected