Hi Uwe, ----- Mail original ----- > De: "Uwe Schindler" <uschind...@apache.org> > À: "core-libs-dev" <core-libs-dev@openjdk.java.net> > Envoyé: Samedi 5 Septembre 2020 13:55:03 > Objet: JDK 15 hidden classes & stack trace visibility
> Hi, > > I am doing a mockup for dynamically compiled scripts in Apache Lucene (later > also painless scripting in elastcsearch), where I tried to use > Lookup#defineHiddenClass (with default parameters, so weak and no nestmates > - but: for painless scripts of Elasticsearch, nestmates will be great). It > all looks great, as sometimes for every query a new class is generated. > > The current approach (Java 8, Java 11) uses a Classloader per script, which > is mostly OK, but hidden classes would be better, especially under high load > with many new classes. The problem I see is: The hidden class and their > methods are also hidden from stack traces, so people neither get the script > source code reference, nor they get the method, which was called at all. > > My question is: is it possible to mark such a hidden class in byte code or > by a flag to defineHiddenClass() so it is "unhidden"? - I know you can do > this by a command line option, but that's for developers and debugging only. > In some cases, this is really wanted (like for scripting languages), but > code still wants to use the better class unloading. If this is not possible, > how about extending the Lookup.ClassOption enum (last parameter of > defineHiddenClass), to also pass a flag to show them in stack traces? If you don't want a hidden class, why not using Lookup.defineClass() for 11 and calling ClassLoader.defineClass() by reflection in 8 ? With defineClass you get a resolvable real name and methods are visible in the stacktrace. Obviously, it means that you are grouping several classes in the same classloader which may be not what you want. > > Uwe Rémi > > ----- > Uwe Schindler > uschind...@apache.org > ASF Member, Apache Lucene PMC / Committer > Bremen, Germany > https://lucene.apache.org/
