The question of the relative speed of Java vs Lisp (in reference
to one particular program) seems to have been answered ---
http://groups.google.com/group/comp.lang.lisp/msg/707a7f3b5c3fb6a9
If I'm not mistaken, the key difference is that the Java program
implements an interpreter in which generated code snippets
are executed, while the Lisp version just punts to its compiler.
Code = data carries the day ...
Interpreting bits of code is common enough, although I'm guessing
it's often a small part of the whole application. In such a situation,
maybe bolting together main application language + Lisp is a
workable approach --- perhaps Java + ABCL (Lisp implementation
in Java) or CL-Python (Python in CL) + SBCL.
FWIW
Robert Dodier