Java 13 adds a new doclint check under "accessibility" that the html
header nesting level isn't crazy.
Many are incorrect because the html4-style javadocs had horrible
font-sizes, so developers used the wrong header level to work around it.
This is no issue in trunk (always html5).
Java recommends against using such structured tags at all in javadocs,
but that is a more involved change: this just "shifts" header levels
in documents to be correct.
Current javadocs declare an HTML5 doctype: !DOCTYPE HTML. Some HTML5
features are used, but unfortunately also some constructs that do not
exist in HTML5 are used as well.
Because of this, we have no checking of any html syntax. jtidy is
disabled because it works with html4. doclint is disabled because it
works with html5. our docs are neither.
javadoc "doclint" feature can efficiently check that the html isn't
crazy. we just have to fix really ancient removed/deprecated stuff
(such as use of tt tag).
This enables the html checking in both ant and gradle. The docs are
fixed via straightforward transformations.
One exception is table cellpadding, for this some helper CSS classes
were added to make the transition easier (since it must apply padding
to inner th/td, not possible inline). I added TODOs, we should clean
this up. Most problems look like they may have been generated from a
GUI or similar and not a human.
Robert Muir
Tomoko Uchida
Dawid Weiss