...when used in patterns like "\\p{someCharacterClass}".
I've used/seen some:
What is the definitive list of all supported built-in character classed? Where is it documented? What are the exact meanings?
There seem to be a lot of "RTFM" answers refering to the javadoc for Pattern. That's the first place I looked before asking this question. Just so everyone is clear, the javadoc for Pattern makes no mention of any of the classes listed above.
The "correct" answer will mention "InCombiningDiacriticalMarks" somewhere on the page, and will not be some vague reference to "Unicode Standards".
The documentation for Pattern says in the "Unicode Support" section:
The supported categories are those of The Unicode Standard in the version specified by the Character class. The category names are those defined in the Standard, both normative and informative. The block names supported by Pattern are the valid block names accepted and defined by
UnicodeBlock.forName.
The documentation for UnicodeBlock.forName states:
Block names are determined by The Unicode Standard.
On http://unicode.org there is the FAQ Where can I find the definitive list of Unicode blocks?:
A: The Unicode blocks and their names are a normative part of the Unicode Standard. The exact list is always maintained in one of the files of the Unicode Character Database,
Blocks.txt.
Finally, in Blocks.txt there is the line:
0300..036F; Combining Diacritical Marks
These characters can be found in the Combining Diacritical Marks code chart (from Unicode 6.0 Character Code Charts).