Salut vickyk, thank you for your helpful reply. In the meantime i was able to connect with my external legacy system. The pooling mechanism is working without any problem. view to the JEE architecture. Anyway, the information is quite rare. Coding a JCA adapter is a bit like coding a device-driver on UNIX for muliple user access. So fine ... "vickyk" wrote : "groovie" wrote : I think, this is the issue of the ConnectionPool-Manager, | | who will disables or remove the connection from the pool | | and try to establish a new one (using my ManagedConnection) | | | Yes Jboss JCA code will call the ManagedConnection's createManagedConnection(..) and matchManagedConnection() while creating the new connection from the pool and retreiving the existing connection from the Pool. | Yes! Everything does work fine for me, but i noticed the invocation of the destroy-Methode in the connectors ManagedConnection implementation. a connection to the legacy systems. Anyway, this does not injure the connectivity, cause the connector does quickly perform a reconnect, but i would like to know the reason for behavour. Inside the service-XML file i noticed the following assignments inside the ManagedConnectionPool tag: 5000 15 Are one of the both settings responsible for the destroy of vital connections ? Thank you for your support Christian Groove View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4269932#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...