The javadoc tool silently ignores @value tag in some cases. I've found 2 such cases so far.
The first one is when one refers to a private constant.
The second one is when a constant is referred to using class#field and the "class" is being imported (e.g.
...
import a.b;
...
{@value b#constant} ...)

In both cases javadoc neither produces documents with displayed constants nor reports any kind of error/warning.