Hi Marco,
Refer 17.4.1 in the spec...
� For a session bean, the transaction attributes must be specified for the methods defined in the bean�s component interface and all the direct and indirect superinterfaces of the component interface, excluding the methods of the javax.ejb.EJBObject or javax.ejb.EJBLocalObject interface. Transaction attributes must not be specified for the methods of a session bean�s home interface.
� For an entity bean, the transaction attributes must be specified for the methods defined in the bean�s component interface and all the direct and indirect superinterfaces of the component interface, excluding the getEJBHome, getEJBLocalHome, getHandle, getPrimaryKey, and isIdentical methods; and for the methods defined in the bean�s home interface
and all the direct and indirect superinterfaces of the home interface, excluding the getEJBMetaData and getHomeHandle methods specific to the remote home interface.
� For a message-driven bean, the transaction attribute must be specified for the bean�s onMessage method.
SCJP 1.4, SCWCD 1.4, SCBCD 1.3, SCEA