Full commercial support is available for the UnboundID LDAP SDK for Java, including access to patches to correct problems identified in the SDK itself, and developer support to assist application developers in using the SDK to create directory-enabled applications. Because the UnboundID LDAP SDK for Java is also under active development, it is also possible to request sensible enhancements and additional functionality.
JNDI is available as part of Java SE, and therefore it is covered by Java SE support contracts. However, this realistically covers only fixes for significant bugs identified in the API, as JNDI does not appear to be undergoing any serious active development. Commercial developer support is also available.
The Netscape Directory SDK for Java does not appear to have any level of commercial support for the API, nor any form of developer support.