AccessibleObject's setAccessible(boolean) is currently not caller sensitive but the overrides in Method/Field/Constructor are. This awkwardness stems from its constructor being protected and the method not being final. It is thus possible to extend the class outside of the java.lang.reflect package and override this method (at least one popular library does this). Ideally the constructor should have been package private and/or the method be final but it's not possible to change this after 20 years.
The consequence of the method in the base class not being caller sensitive is that it's possible to use a minimally trusted lookup to get a method handle to the method. Paul, Mandy and I chatted about this one recently. We prototyped changes to the MH implementation to special case this method and treat it "as if" it is caller sensitive. This maximizes compatibility but has the downside that it makes it harder to audit and somewhat fragile. In the end, we concluded it would be simpler to add the @CS annotation to this method so that it is treated consistently. The downside of this is that custom AccessibleObject implementations need to override setAccessible if they want to be invoked using method handles obtained from a minimally trusted lookup.
The proposed changes are simple. The removal of "checkMemberAccess" from canBeCalledVirtual is just a clean-up because this method is no longer needs special casing (it was degraded for Java SE 10 as envisaged in JEP 176). It's not the goal here to improve the performance of canBeCalledVirtual but there may be opportunities to look at that with a separate issue:
http://cr.openjdk.java.net/~alanb/8196830/webrev/ -Alan
