Interplatform (interprocess, interlanguage) communication

  ?X? below is another language than Java, for example,
  VBA, C#, or C.

  When an X process and a Java process have to exchange
  information on the same computer, what possibilites are
  there? The Java process should act as a client, sending
  commands to the X process and also wants to read answers
  from the X process. So, the X process is a kind of server.

  My criteria are: reliability and it should not be extremely
  slow (say exchanging a string should not take more than
  about 10 ms). The main criterion is reliability.

  ?Reliability? means little risk of creating problems, little
  risk of failure at run-time. (It might help when the client
  [=Java process] can reset the communication to a known and
  sane start state in case of problems detected at run-time.)

  The host OS is Windows, but a portable solution won't hurt.

  A list of possibilities I am aware of now:

  Pipes

  I have no experience with this. I heard one can establish
  a new process ?proc? with ?exec? and then use

BufferedWriter out = new BufferedWriter(new
  OutputStreamWriter(proc.getOutputStream()));
BufferedReader in = new BufferedReader(new
  InputStreamReader(proc.getInputStream()));

  Files

  One process writes to the end of a file, the other reads
  from the end of the file? - I never tried this, don't know
  if it is guaranteed to work that one process can detect and
  read, whether the other has just appended something to a file.

  What if the processes run very long and the files get too
  large? But OTOH this is very transparent, which makes it easy
  to debug, since one can open the files and directly inspect
  them, or even append commands manually with ?copy con file?.

  Sockets

  This is slightly less transparent than files, but has the
  advantage that it becomes very easy to have the two
  processes running on different computers later, if this
  should ever be required. Debugging should be possible
  by a man-in-the-middle proxy that prints all information
  it sees or by connecting to the server with a terminal.

  JNI

  JNI might be used to access code written in C or
  ABI-compatible languages. This should be fast, but I heard
  that it is error prone to write JNI code and needs some
  learning (code less maintainable)?