The comments in the code suggest it isn’t needed since Java 8, which is used for the current downloads. And although I realise that ImageJ can still be built with Java 6, this hasn’t been updated since 2013 and reached end of support in 2018.
The problem is that MacAdapter doesn’t belong to a specific package, and Java’s new(ish) module system really doesn’t like that. This makes it very awkward to include ImageJ1 as a dependency in a modular application.
If it could be removed – or somehow added to a package – that would remove one modularization headache I’ve been grappling with in QuPath… and I guess might benefit others as modular applications become more common, and anything below Java 8 falls into disuse.
PS. See also: