[tr064] Address book unavailable due to "IllegalStateException: Duplicate key" when phone numbers are not unique

Hi guys,

I am using openhab3 and tr046 binding and the phonebook feature for fritzbox. In principle all works fine. However, there is a challenge for my setup that is certainly relevant for others.

In my address book, I have the same phone number in two entries. There are two cases:

same number in two contacts (e.g. fixed line of my brother and his wife)
same number in one contact (e.g. because entries coming from an exchange server contain the same number as "mobile" and "work")

These cases, here shown for the second case, lead to a warning:

2021-03-14 13:00:15.924 [WARN ] [mmon.WrappedScheduledExecutorService] - Scheduled runnable ended with an exception: 
java.lang.IllegalStateException: Duplicate key +491XXXXXXXXXX (attempted merging values Doe, John and Doe, John)
    at java.util.stream.Collectors.duplicateKeyException(Collectors.java:133) ~[?:?]
    at java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:180) ~[?:?]
    at java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169) ~[?:?]
...

Reason for this error is that the number +491XXXXXXXXXX is configured as both, mobile and work number of John Doe. Unfortunately I cannot change that because it is coming from the exchange server at my work.

The result is that the address book is not available at all. I think it would be reasonable that the value (name) for the key (phone number) is simply overwritten by the last entry.

openhab / openhab-addons

[tr064] Address book unavailable due to "IllegalStateException: Duplicate key" when phone numbers are not unique #10327