In the spirit of moving things from JabRefPreferences, wouldn't it make sense to let the ProxyPreferences class access the preferences directly?

So: ProxyPreferences proxyPrefs = new ProxyPreferences() and proxyPrefs.save() (possibly with a JabRefPreferences as an argument).

Yes you are right, this would also be a possibility.

What I aim at in the end is to reduce the public interface of the JabRefPreferences class to like 20 methods which store/retrieve only complex types. In this way also the serialization is hidden in the class and the caller doesn't have to worry how to convert to string/boolean etc. Then it would be also very simple to replace the whole class with something completely different, for example writing the preferences as a json file.

I now moved some code from the JabRefPreferences class to the new ProxyPreferences class as @oscargus suggested. Looks indeed cleaner.

• no state in ProxyPreferences
• IDEA: logic and model should not know JabRefPreferences
• JabRefPreferences must not know ProxyPreferences; defaults and keys in JabRefPrefences

Done & rebased.