cf. http://markmail.org/message/zvwyy5csr3bi4whj The 'closeMethod' attribute is documented in the <Context> documentation, but in neither the "JNDI Resources" page of the users' guide nor the "Resources" page of the configuration guide. Thus, it's a little tough to find out about this configuration option.
It is also documented under GlobalResources. It should not be listed under the Resources page in the configuration guide as that does not refer to JNDI resources. I've added some text to the JNDI how-to for trunk and 7.0.x Will be in 7.0.37 onwards.