Initial versions (including the preview in 7/M3) of the JSR 292 API use an undesirable technique for data structure factoring, implementation inheritance. The types MethodHandle and JavaMethodHandle both inherit from JVM-internal supertypes. This pollutes their API, makes unreadable "holes" in their javadoc, and breaks the API filtering performed by javac (as driven by the file "lib/ct.sym").
A stopgap solution (for javac and the ct.sym file) is to place sun.dyn on the list of packages to allow but not to document.
The real solution is to remove those private supertypes from those public types.
Because the implementation types are special-cased by the JVM, this will require a coordinated JVM and java change, with the JVM changes coming first.
Also, inheritance from MethodHandle must not be exposed via protected or public constructors.
Fixing this bug must remove all "sun.misc" types from the MethodHandle API.