[sirn]

You can skip xargs altogether with the plus sign instead of semicolon.

    -exec utility [argument ...] {} +
            Same as -exec, except that ``{}'' is replaced with as many path-
            names as possible for each invocation of utility.  This behaviour
            is similar to that of xargs(1).

The problem with just wc -l *.java is that it don't recursive directory.

[jedbrown]

With bash-4 or zsh

  wc -l **/*.java