Can't access lower-case static fields shadowed by static methods

[headius]

Discussed in #8187

^{Originally posted by mrckzgl April 3, 2024}
Hey, we want to access the enums in this class: https://tinkerpop.apache.org/javadocs/current/core/org/apache/tinkerpop/gremlin/structure/VertexProperty.Cardinality.html from within JRuby.
Before an upgrade of the gremlin jar this worked with: org.apache.tinkerpop.gremlin.structure.VertexProperty::Cardinality::single, but after the upgrade, static methods with the same name as the enums were added to the class (e.g. https://tinkerpop.apache.org/javadocs/current/core/org/apache/tinkerpop/gremlin/structure/VertexProperty.Cardinality.html#single(java.lang.Object). Now if we try to access the enums, JRuby complains about a missing parameter, which indicates that it instead accesses the static method.

How to distinguish between static enum and static method?

The problem is that the library defines lower-case enum. These were accessible via MyEnum::lowername before, but then the library added in static methods with the same names. Now the methods win in JRuby's proxy class, so there's no way to access the enum values anymore.

[headius]

A workaround for now is to just use reflection directly to access the enum values (which are normal static fields):

[] jruby $ cat Blah.java
public enum Blah {
    blah1, blah2;

    public static void blah1() {}
}
[] jruby $ jruby -e 'p Java::Blah.blah1, Java::Blah.blah2'
nil
blah2
[] jruby $ jruby -e 'p Java::Blah.java_class.get_field("blah1").get(nil), Java::Blah.blah2'
blah1
blah2

I believe we should have java_field that can support static fields, but I could not get it to work with the current implementation.