JNDI is optimised for these types of queries (search often update rarely) but there are some differences in performance. Database make some concessions to allow faster updates.
the main reason for using JNDI (from my perspective) is that it is what everyone else is doing so if you access these resources in a database it will be more difficult to maintain.
plus remember that jndi is a hierarchical data source - it is ideal for hierarchical data, while database is a complex relational thing - again, the optimisations that are made are significant under large loads.
finally, companies with existing LDAP solutions will want you to use them to maximise on their ROI and it is sometimes important to seperate configuration details from consumable data.
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Chanoch Wiggers
Architect for
Professional Java Mobile Programming