Prepared statements are most definitely tied to a connection. Since in jboss you can't hold onto a connection over transaction boundaries, holding onto a prepared statement will do you even less good. Some drivers implement prepared statement caching themselves.

However, note that if you are using XADataSourceLoader with the XADataSourceImpl or ConnectionFactoryLoader with the jdbc (local transaction, not xa) wrapper, the jboss wrappers do prepared statement pooling for you.