On Wed, 25 Nov 2020 22:24:40 GMT, Mandy Chung <mch...@openjdk.org> wrote:
>> This proposes a new static `Proxy::invokeDefaultMethod` method to invoke >> the given default method on the given proxy instance. >> >> The implementation looks up a method handle for `invokespecial` instruction >> as if called from with the proxy class as the caller, equivalent to calling >> `X.super::m` where `X` is a proxy interface of the proxy class and >> `X.super::m` will resolve to the specified default method. >> >> The implementation will call a private static `proxyClassLookup(Lookup >> caller)` >> method of the proxy class to obtain its private Lookup. This private method >> in the proxy class only allows a caller Lookup on java.lang.reflect.Proxy >> class >> with full privilege access to use, or else `IllegalAccessException` will be >> thrown. >> >> This patch also proposes to define a proxy class in an unnamed module to >> a dynamic module to strengthen encapsulation such that they are only >> unconditionally exported from a named module but not open for deep reflective >> access. This only applies to the case if all the proxy interfaces are public >> and in a package that is exported or open. >> >> One dynamic module is created for each class loader that defines proxies. >> The change changes the dynamic module to contain another package (same >> name as the module) that is unconditionally exported and is opened to >> `java.base` only. >> >> There is no change to the package and module of the proxy class for >> the following cases: >> >> - if at least one proxy interface is non-public, then the proxy class is >> defined >> in the package and module of the non-public interfaces >> - if at least one proxy is in a package that is non-exported and non-open, >> if all proxy interfaces are public, then the proxy class is defined in >> a non-exported, non-open package of a dynamic module. >> >> The spec change is that a proxy class used to be defined in an unnamed >> module, i.e. in a exported and open package, is defined in an unconditionally >> exported but non-open package. Programs that assume it to be open >> unconditionally >> will be affected and cannot do deep reflection on such proxy classes. >> >> Peter Levart contributed an initial prototype [1] (thanks Peter). I think >> the exceptions could be simplified as more checking should be done prior to >> the invocation of the method handle like checking the types of the arguments >> with the method type. This approach avoids defining a public API >> `protected Proxy::$$proxyClassLookup$$` method. Instead it defines a >> private static method that is restricted for Proxy class to use (by >> taking a caller parameter to ensure it's a private lookup on Proxy class). >> >> javadoc/specdiff: >> http://cr.openjdk.java.net/~mchung/jdk16/webrevs/8159746/api/ >> http://cr.openjdk.java.net/~mchung/jdk16/webrevs/8159746/specdiff/ >> >> [1] >> http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-June/041629.html > > Mandy Chung has updated the pull request with a new target base due to a > merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains 25 additional > commits since the last revision: > > - Merge branch 'master' of https://github.com/openjdk/jdk into > proxy-default-method > - update copyright header > - clean up DefaultMethodProxy test > - Performance improvement contributed by plevart > - Clean up the patch. Rename to > - Merge branch 'master' of https://github.com/openjdk/jdk into > proxy-default-method > - move invokeDefaultMethod to InvocationHandler and throw IAE if access > check fails > - Merge branch 'master' of https://github.com/openjdk/jdk into > proxy-default-method > - Merge branch 'master' of https://github.com/openjdk/jdk into > proxy-default-method > - minor tweak to the spec wording and impl > - ... and 15 more: > https://git.openjdk.java.net/jdk/compare/5fcea495...d72d627f src/java.base/share/classes/java/lang/reflect/Proxy.java line 1227: > 1225: if (proxyInterfaces.contains(declaringClass)) > 1226: return declaringClass; > 1227: It might be beneficial for future maintainers if you could include a comment here on the search order. ------------- PR: https://git.openjdk.java.net/jdk/pull/313
