As a follow-up to the ongoing review for JDK-8241618, I have also looked
at fixing the deprecation warnings in jdk.hotspot.agent. These fall in
three broad categories:
* Deprecation of the boxing type constructors (e.g. "new Integer(42)").
* Deprecation of java.util.Observer and Observable.
* The rest (mostly Class.newInstance(), and a few number of other odd
The first category is trivial to fix. The last category need some
special discussion. But the overwhelming majority of deprecation
warnings come from the use of Observer and Observable. This really
dwarfs anything else, and needs to be handled first, otherwise it's hard
to even spot the other issues.
My analysis of the situation is that the deprecation of Observer and
Observable seems a bit harsh, from the PoV of jdk.hotspot.agent. Sure,
it might be limited, but I think it does exactly what is needed here. So
the migration suggested in Observable (java.beans or
java.util.concurrent) seems overkill. If there are genuine threading
issues at play here, this assumption might be wrong, and then maybe
going the j.u.c. route is correct.
But if that's not, the main goal should be to stay with the current
implementation. One way to do this is to sprinkle the code with
@SuppressWarning. But I think a better way would be to just implement
our own Observer and Observable. After all, the classes are trivial.
I've made a mock-up of this solution, were I just copied the
java.util.Observer and Observable, and removed the deprecation
annotations. The only thing needed for the rest of the code is to make
sure we import these; I've done this for three arbitrarily selected
classes just to show what the change would typically look like. Here's
Let me know what you think.