An anonymous class appearing in JShell is rewritten to something that gets interpreted as a member class:

jshell> new Object(){}.getClass()
$1 ==> class $0

jshell> $1.isAnonymousClass()
$2 ==> false

jshell> $1.isLocalClass()
$3 ==> false

jshell> $1.isMemberClass()
$4 ==> true

This affects the behavior of other methods like 'getSimpleName' and 'getCanonicalName'.

I don't know the translation strategy, but perhaps it could be adjusted to give javac a true anonymous class?