As i have understood ,UDDI registry is a registry where a company/organisation registers its web services so that other parties can find and use them.
But i am not sure whether its a global registry i.e all companies has to register to a particular specific registry or its upto the individual companies to have there own registry and make them available on the internet.
There used to be a few global registries that were publicly accessible, but since UDDI hasn't taken off (at least not in the way that was envisaged), those have been shut down. Given that, there isn't much value in using UDDI.
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