Not through processing directly, but Java 1.5 and greater have the System.nanoTime() method, which may or may not give you useful information (no guarantees are made as to how often the nanotimer is updated).  See http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html#nanoTime()  for information.

If you'd rather not follow the link, try this, which is the example there:

  long startTime = System.nanoTime();
  // ... the code being measured ...
  long estimatedTime = System.nanoTime() - startTime;

May at least give you somewhere to start...though if you're targeting 1.4, you're probably out of luck unless you want to do some native method hacking.