On constant folding of final field loads (original) (raw)

Vladimir Ivanov vladimir.x.ivanov at oracle.com
Mon Jun 29 12:00:57 UTC 2015

Paul,

For MHs it's not possible to lookup a MH (via MH.L.findSetter/unreflectSetter) to a final field.

http://hg.openjdk.java.net/jdk9/dev/jdk/file/93ced310c728/src/java.base/share/classes/java/lang/invoke/MethodHandles.java#l1516 Although i cannot find any such explicit mention in JavaDoc, so i guess it can be considered under the umbrella of "access checks". Though you can't lookup a setter for al final field directly, you can use Lookup.unreflectSetter: Field f = T.class.getDeclaredField("t"); f.setAccessible(true); MethodHandle setter = MethodHandles.lookup().unreflectSetter(f);

But it doesn't matter much, since MH field getters/setters are baseon on Unsafe. So, if final field value tracking works for Unsafe, it works for j.l.i as well.

Best regards, Vladimir Ivanov

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