The spec for the methods Executors.privilegedThreadFactory() and Executors.privilegedCallableUsingCurrentClassLoader(...) says:
"Throws: AccessControlException - if the current access control context does not have permission to both set and get context class loader"

It should be specified in obvious way which exactly permissions required to get/set context class loader.
For example:
Throws: AccessControlException - if the current access control context does not have RuntimePermission("getContextClassLoader") and RuntimePermission("setContextClassLoader")