On Wed, 7 Jun 2023 14:15:10 GMT, Chen Liang <li...@openjdk.org> wrote:
>> Add API to explore Class Hierarchy with a `ClassLoader` or a `Lookup` with >> proper privileges, with tests. >> >> This addition is useful in case classes at runtime are not loaded from the >> system class loader, such as Proxy. This is also useful to APIs that >> generate bytecode with a `Lookup` object, such as a custom >> single-abstract-method class implementations from a method handle. >> >> See >> https://mail.openjdk.org/pipermail/classfile-api-dev/2023-March/000249.html >> as well. >> >> Current questions, which I wish to discuss with @asotona: >> 1. Should the resolver fail fast on `IllegalAccessException` from the >> lookup? This usually indicates the hierarchy resolver is set up improperly, >> and proceeding may simply yield verification errors in class loading that >> are hard to track. For bytecode-generating APIs, throwing access errors for >> the Lookup eagerly is also more preferable than later silent generation >> failure. >> 2. Whether the default resolver should be reading from jrt alone, reflection >> alone, or jrt then reflection. I personally believe reflection alone is more >> reliable, for classes may redefined with instrumentation or jfr, which may >> not be reflected in the system resources. >> 3. In addition, I don't think chaining system class loader reflection after >> system resource retrieval is really meaningful: is there any case where >> reflection always works while the system resource retrieval always fails? > > Chen Liang has updated the pull request with a new target base due to a merge > or a rebase. The pull request now contains 14 commits: > > - Review changes, fixed tests > - Merge branch 'master' into hierarchy-resolve > - 1. Moved the default resolver to a static method, in anticipation of > future changes > 2. Removed SecurityManager related content > 3. Changed ClassHierarchyInfo into an interface > 4. Moved caching method from static to instance method > - Merge branch 'master' into hierarchy-resolve > - rename to ofClassLoading/ofResourceParsing > convert the default class provider to bypass security manager restrictions > - Merge branch 'master' into hierarchy-resolve > - Merge branch 'master' into hierarchy-resolve > - Test both cached and uncached resolvers > - Update the class hierarchy resolver api as per mailing list last week > - Merge branch 'master' into hierarchy-resolve > - ... and 4 more: https://git.openjdk.org/jdk/compare/a1ab377d...90645b6f src/java.base/share/classes/jdk/internal/classfile/impl/Util.java line 103: > 101: } > 102: return descOrInternalName.substring(1, > descOrInternalName.length() - 1).replace('/', '.'); > 103: } else { Note that this won’t work right if this method is called with the internal name of a class whose FQCN starts with `L`, the correct implementation would be: Suggestion: if (descOrInternalName.startsWith("L") && descOrInternalName.endsWith(";")) { // descriptors of classes or interfaces if (descOrInternalName.length() <= 2) { throw new IllegalArgumentException(descOrInternalName); } return descOrInternalName.substring(1, descOrInternalName.length() - 1).replace('/', '.'); } else { ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13082#discussion_r1226031008
