The java.text package has a number of entirely undocumented methods. An up-to-date list can be found at
http://javaweb.eng/docs/writing/jdk/kestrel/checkdoc/checkdoc_Package-java.text.html

The affected classes are ChoiceFormat, DecimalFormat, DecimalFormatSymbols, Format, MessageFormat, NumberFormat.

Requirements for writing API specifications can be found at
http://javaweb.eng/sqe/compatibilityKits/testDev/JavaAPISpec.html