On 6/25/13 3:50 AM, Peter Levart wrote:
Hi,
I know that @CallerSensitive annotation was introduced to bring some
order to JDK internal plumbings. It's scope was to support JDK
internal usage, so it's use is limited to classes loaded by bootstrap
or extension class-loaders. In JDK-internal code it is used mainly for
implementing security-sensitive decisions. But since the
sun.reflect.Reflection.getCallerClass(int) was public and
unrestricted, it found it's way out into user code, where at least I
know that it is used in two areas:
1 - to locate callers in the whole call-stack so that their location
in class-path can be reported (Log4J is an example)
2 - to locate immediate caller so that some resources associated with
it can be located and used (for example localization data in GUI
applications)
I don't know how wide-spread 1st usecase is, but the 2nd is common,
since it's use enables APIs that need not explicitly pass-in the
calling class in order to locate resources associated with it (and/or
the class-loader of it). So it would be nice to have such supported
API in JDK8 at least.
It's good to know these use cases. We leave the method in 7 update
release so as to allow time for applications to transition and also
determine any use case that the SE API should provide if there is no
replacement for it.
I'm asking here, to hear any arguments against making such API
supported and public. Are there any security or other issues? If there
aren't, what steps should be taken to introduce such API in the JDK8
timeframe? I'm thinking of a no-arg method, say j.l.Class.getCaller()
and moving @CallerSensitive to a supported package + enabling it to
mark methods in any class (not just system and ext classes)...
Besides providing a method returning the caller's class, I'd like to
consider what other options we have and different use cases could be
satisfied by different API. For #2, the problem is that the API to find
a resource, it requires to use the ClassLoader with the right visibility
(the caller's class loader). This is similiar to 8013839 : Enhance
Logger API for handling of resource bundles [1]. For example, a static
method Class.getResource to use the caller's class loader to find the
given resource might be an alternative?
About the timeframe, the API freeze date [2] is Oct 10. If the API is
simple and small effort (test development, security assessement, etc),
there is chance to get that in for jdk8.
Mandy
[1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8013839
[2] http://openjdk.java.net/projects/jdk8/milestones#API_Interface_Freeze
