First make sure you are indexed with
gw -index
(it normally does that automatically, but won't if you interrupt it).
You should be able to find that using the phrase "java lang System".
If you want to search for terms with . in them, you will have to add
an index expression (-k) to index them. e.g.:
gw -unindex
gw -k"\alnum{2,30}" -k"[\alnum.]{2,40}" -index
Or if you're starting a walk on a fresh database:
gw -k"\alnum{2,30}" -k"[\alnum.]{2,40}" http://the_url_to_walk
See also http://www.thunderstone.com/gw25man/node40.html