On 11/24/20 10:21 AM, Simone Bordet wrote:
Hi,
testing the Jetty MethodHandle usages we encountered this situation:
.class org.openjdk.mh.Main
----
Class<?> klass = Main.class;
MethodHandles.Lookup lookup = MethodHandles.publicLookup().in(klass);
MethodHandle handle = lookup.findVirtual(klass, "test",
MethodType.methodType(String.class));
----
.module-info.java
----
module org.openjdk.mh {
exports org.openjdk.mh to com.acme;
}
----
findVirtual() throws:
java.lang.IllegalAccessException: symbolic reference class is not
accessible: class org.openjdk.mh.Main, from
org.openjdk.mh.Main/noaccess (module org.openjdk.mh)
Removing the "to" clause from the exports in module-info.java fixes the issue.
Seems that a class cannot get a MethodHandle on itself, the reason
being that org.openjdk.mh is selectively exported in module-info.java.
You use MethodHandles::publicLookup which has access to unconditionally
exported classes only. It can't be used to teleport to a
qualified-exported class. You can use MethodHandles.lookup().in(klass)
instead.
Is this intended behavior?
Yes, it's intended behavior.
Mandy
I would have expected that a class could always get a MethodHandle on itself.
I tested this with 11, 15, and 16+25, all fail.
I have a simple reproducer, and I can open an OpenJDK bug.
Thanks!