On http://poi.apache.org/guidelines.html in section "checklist before submitting a patch" the link to "coding standards" is broken (404 not found).
Good spot, fixed in r1496502.
Minimal Coding Standards at http://poi.apache.org/resolutions/res001.html is missing again (linked to by http://poi.apache.org/guidelines.html#CodeStyle).
Ah, needed a relative link, not an absolute one to get generated. Fixed again in r1617744.