watanabe-mincho and wadalab-gothic font is defined by font.properties.ja.
However, those two fonts are ugly glyph and poor. I attached jpg files, see
those files. it is easy to compare which font is beautiful.
so if user requires to use the other optional fonts instead of watanabe-mincho
and wadalab-gothic font, they had to reconfig font.properties.ja.
But optional font install bacame easy to setup by keyword "appendedfontpath"
in 4492212.

watanabe-mincho and wadalab-gothic is being used until RedHatLinux7.x
as default font.
RedHatLinux7.2 also contains watanabe-mincho and wadalab-gothic.
And more kochi font contains as default, too. kochi font is free font and
it is updated versioin of watanabe and wadalab font and more it has halfwidth
katakana glyph. Although halfwidth katakana glyph was not included in watanabe
and wadalab font, kochi font includes halfwidth katakana glyph.

c.f) Kochi font
http://www.on.cs.keio.ac.jp/~yasu/jp_fonts.html <-Japanese only

 
font.properties.ja is being prepared for each RedHat versions.
I suggest to make kochi font as java default font for RedHatLinux7.2.