[BUG] java.util.Properties.entrySet() does not override java.lang.Object methods since Java 9

[Roger Riggs]

Hi Rob,

Thanks for the report, an issues has been created:
https://bugs.openjdk.java.net/browse/JDK-8245694

Regards, Roger


On 5/23/20 3:13 PM, Rob Spoor wrote:
> Hi,
>
> I was working on upgrading a library of mine from Java 8 to 11, and I 
> noticed my unit tests started failing. Some investigation showed that 
> in Java 9, java.util.Properties was rewritten to no longer rely on the 
> fact that it extends Hashtable. One of the changes was to use a 
> private static class called EntrySet. However, while this class 
> implements most methods from java.util.Set, it's actually missing two: 
> equals and hashCode. As a result it does not adhere to the general 
> contract of java.util.Set. It's also missing a toString 
> implementation, thereby inheriting its String representation from 
> java.lang.Object. I've checked the source code up to Java 14, and even 
> the Mercurial repository, and this issue still exists.
>
> I think this could be solved as simply as by having this private 
> EntrySet class extend AbstractSet, or otherwise delegate its methods 
> to its entrySet field. The latter is probably preferred, as it matches 
> the implementation of the same methods of the java.util.Properties 
> class itself.
>
> Rob