The ASCII class trees need equivalent text.

  Priority 1
  Section 508 1194.22(a)
      A text equivalent for every non-text element shall be provided
      (e.g., via "alt", "longdesc", or in element content)
  W3C Checkpoint 1.1
       http://www.w3.org/TR/WCAG10-CORE-TECHS/#text-equivalent
       "Text equivalents mus be provided for every non-text element ...
        This includes ASCII art..."

The ASCII art under consideration is the vertical line, horizontal line
and plus sign:

   java.lang.Object
    |
    +--java.lang.String