Probleme de Config Tomcat et Mysql + JDBC

Bonjour,

J'ai un problème de connexion à la base avec le JDBC; sur mon projet java, j'ai ces erreurs à l'exécution :

DEBUG main org.hibernate.util.JDBCExceptionReporter - SQL Exception
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

WARN main org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: null
ERROR main org.hibernate.util.JDBCExceptionReporter - Cannot create PoolableConnectionFactory (Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)
WARN main org.hibernate.cfg.SettingsFactory - Could not obtain connection to query metadata
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)

Mon environnement de travail:
Mac OS 10.6
Eclipse 3.5
Tomcat 5.5.33
Mysql 5.5.9
JDBC 5.1.16 (je compte essayer avec JDBC 5.0.8)

Des consignes ou des conseils ou des remarques sont les bienvenues ???

Merci