Java portgroup default fallback?

[Joshua Root]

Does anyone know why there is no default value for java.fallback? The 
assumption appears to be that if a port is using this portgroup, it 
requires Java, since it errors out in pre-fetch if no Java is found. So 
it seems like having no fallback by default is just causing builds to 
fail unnecessarily.

If a default fallback is appropriate, what should it be? My initial 
impression is that the latest LTS openjdk that works on the current OS 
would be reasonable.

- Josh