Comment on precompiled in 1.4 source?

Question

In 1.4 the java.nio.ByteBuffer class is documented.
But there is no java file for that class in the source.
There are several interesting files with a 'X' in the name.
This is the code from the top of ByteBufferAs-X-Buffer.java
  #warn This file is preprocessed before being compiled
  package java.nio;
  class ByteBufferAs$Type$Buffer$RW$$BO$               // package-private
    extends {#if[ro]?ByteBufferAs}$Type$Buffer{#if[ro]?$BO$}
  #if[rw]
    protected final ByteBuffer bb;
    protected final int offset;
#end[rw]
...Obviously not java.
Anyone recognize the precompiler syntax? It certainly isn't C/C++.
I would like a reference to the manual that explains this, if anyone knows what it is.
Presumably ByteBuffer comes from X-Buffer.java. That is preprocessed as well.

Answer 1

Either I am mis-reading the responses above or there is a misunderstanding about what I want.
I am not interested in the following:
-Instructions on building the source
-The java source for ByteBuffer.
-Explainations of what a pre-processor does (or how it works.)
I am interested in documentation or even the name of the specific tool use to pre-process the the files in the sun source tree.
There are several possibilities...
Now presumably this is something that exists on windows. Because without it, it means that building the windows jdk is a two step process, a unix build and a windows build. (And having worked with that before it can be a real nightmare.) Now they might be using a common (or not so common) unix tool that has been ported to windows. If that is the case and I knew the name, then I could find the documentation.
Or they could have written a pre-processor. If so then it should exist in the source tree. In this case there might not be any documentation. But I might be able to figure out the rules if I knew where to look.
Or they could have written it, but it is not in the source tree. But then the source tree is not buildable.