bug: hashCode/equals is broken for clients/scopes/NativePersistenceCacheEntity

[yuriyz]

Describe the issue

bug: hashCode/equals is broken for clients/scopes/NativePersistenceCacheEntity

There are a few symptoms of this:

• When calling the end_session service when there are multiple clients in a session, validation of the post_logout_redirect_uri fails for all but one of them
• If post_logout_redirect_uri validation succeeds for the lucky client, the other clients don't receive their front-channel logout.
  Cutting to the chase, it looks like the issue was introduced with this commit.

With this change, org.gluu.oxauth.model.registration.Client now inherits the hashCode() and equals() methods from org.gluu.persist.model.base.Entry.

This is a problem because org.gluu.oxauth.model.registration.Client overrides the dn property of Entry, such that hashCode() and equals() are now being computed based on Entry's dn, which is null.

This causes "very bad things" to happen with collections of Clients, for example: here where only the first client ever gets added to the resulting Set since all instances of Client have the same hashCode and are equals() to each other.

Support: 10366

[yuriyz]

Issue is fixed in jans, oxauth 4.4.0 (master) and 4.3.2.