Hi all,
I did spent some time to think about the problem with using JDK9
specific API in our build.
One very basic problem is that the jigsaw parts of JDK9 are still in the
move. API is still changing, and so do command line options. Thus let us
here concentrate on AccessiblebObject#trySetAccessible in this mail
The basic problem is us doing setAccessible. WE need to do this though,
but without the command line option --permit-illegal-access
setAccessible would fail. So this will be a required option very often.
The next problem is that --illegal-access is printing warnings about who
tried to do setAccessible. In our test build that amounts to 44k
warnings. There will be a new option
--illegal-access=<value>
permit or deny access to members of types in named
modules
by code in unnamed modules.
<value> is one of "deny", "permit", "warn", or "debug"
This option will be removed in a future release.
now, independent of what is set here, we still do not want a warn cause
thousands of warning messages.... which is why we should use
trySetAccessible instead of setAccessible, to avoid that. But this is
JDK9 only.
Now Remi was suggesting quite some time to go with a patched JDK for
compilation in javac. We would not run against this class, it is only to
compile against (using bootclasspath patching).
I think is technically possible, but I fear licensing problems. We can
for example not easily just provide the class in bytecode form, since
that means a binary in the source distribution of apache. We can imho
also not just take the class from the OpenJDK and add it to our build,
because then we would distribute a class under GPL. And even if we only
compile against it, this would require a "go" from apache legal in my
opinion. The next option would be to generate a AccessiblebObject class,
which contains all the signatures, but doesn't have to have bodies for
the methods. Problem here: we have to ensure the changes to this class
are reflected in our stub.
And the other way would be to require JDK9 to build. I think this is
possible now.
I would like to hear some thoughts on this before I start acting.
bye Jochen
