just-in-time

from The Free On-line Dictionary of Computing (8 July 2008)
dynamic translation
JIT
just-in-time

   <architecture> A {virtual machine} implementation approach,
   used to speed up execution of {byte-code} programs.  To
   execute a program unit such as a {method} or a {function}, the
   virtual machine compiles its bytecodes into (hardware) machine
   code.  The translated code is also placed in a cache, so that
   next time that unit's machine code can be executed
   immediately, without repeating the translation.

   This technique was pioneered by the commercial {Smalltalk}
   implementation currently known as {VisualWorks}, in the early
   1980s.  Currently it is also used by some implementations of
   the {Java Virtual Machine} under the name {JIT} (Just In Time
   compilation).

   [Peter L. Deutsch and Alan Schiffman. "Efficient
   Implementation of the Smalltalk-80 System", 11th Annual
   Symposium on Principles of Programming Languages, Jan 1984,
   pp. 297-302].

   (2002-04-15)