Hi Alan, I was trying to fix Groovy to use trySetAccessible() instead of setAccessible() and this did not change any warnings at all: The code can be found here:
https://github.com/apache/groovy/compare/master...uschindler:java9/trySetAccessible It did not change anything. In fact, the code behaved as it did before - no change at all! Warnings are almost the same (actually worse, because of how I did it using MethodHandles, see bwlow). It also granted full access, like the usual call to setAccessible()! As Jochen said: > Now I am told those warnings appear here as well. I was the one who told it to him indirectly... because I tried to fix it for Groovy with the above code change! It granted access to internal API as it did before and it also printed the warning - so the new API was identicak to a simple call to setAccessible. Why is the new AI there at all, setAccessible did the same. And an if/then/else vs. a try/catch is not really different! Sorry, I expected trySetAccesible() to behave differently: As this is a *new* API in Java 9, I would have expected that the "big kill switch" does not affect this! So when calling this new API, I would have expected that it would behave as follows: - It would *not* grant access to internal APIs, as specified in the Java 9 spec and the module system. As the API is new, there s no need for it to respect the "big kill switch" aka "permit-illegal-access". - It would not print a warning at all! In fact the new code in the above patch to Groovy was much more confusing, as the warning was suddenly printed by a JDK-internal class - which is a bug IMHO: The JDK printed a warning like this: WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by org.codehaus.groovy.reflection.InjectedInvoker/1364880320 (file:/C:/Users/Uwe%20Schindler/Projects/groovy/target/classes/java/main/) to method java.lang.Object.finalize() WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.InjectedInvoker/1364880320 WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release This came from the fact, that the internal wrapper of the MethodHandle, which was created by the call to trySetAccessible() using a MethodHandle. I suppose it was used to make the caller-sensitive stuff work correctly. So I was baffled, because the warning was not really helpful anymore! The class mentioned here does not even exist anywhere!!! ☹ Uwe ----- Uwe Schindler uschind...@apache.org ASF Member, Apache Lucene PMC / Committer Bremen, Germany http://lucene.apache.org/ > -----Original Message----- > From: jigsaw-dev [mailto:jigsaw-dev-boun...@openjdk.java.net] On Behalf > Of Alan Bateman > Sent: Monday, July 10, 2017 10:07 AM > To: Jochen Theodorou <blackd...@gmx.org>; jigsaw-dev@openjdk.java.net > Subject: Re: trySetAccessible > > On 10/07/2017 00:16, Jochen Theodorou wrote: > > Hi all, > > > > since the JVM now prints warnings if you call setAccssible there was > > the advise to move to trySetAccessible to prvent these warnings. > The motivation for trySetAccessible is to avoid using exceptions for > control flow. I don't recall any suggestion here to use it as a way to > avoid warnings. > > Remember the purpose of the warnings is to make you or your users aware > that the code will behave differently when access to JDK internals, or > other so-called illegal access, is denied. > > -Alan
