Which and where- what?

I can never remember how to do this on windows or *nix so I'm putting it here. How do you figure out where that executable that is in your path is coming from?

In *nix:

$ which java
/usr/bin/java
$

I don't know if there is a similar animal in windows but this gets close enough:

c:\>where java
c:\windows\system32\java.exe

c:\>