Re: ADA vs JAVA sockets

[David Marceau <davidmarceau@sympatico.ca>]

Frode Tenneb� wrote:
> 
> On Wednesday 07 January 2004 09:39 Riccardo wrote:
> 
> > Can I say thet JAVA brings such kind of problems?
> > (the same program in ADA works fine with an application written in
> > C++)
It was just luck that you seemed to have no problem.
UDP packets are not guaranteed to be delivered.

If using UDP packets, essentially you could assign some kind of ticket number to
every UDP packet and and then ensure at the receiving end you got all the
tickets.  There is the possibility that the order of reception is not as
expected either and you have to sort/assemble them in the correct order at the
receiving end.  There is also the possibility that you need to request a
specific packet with a specific ticket number to be resent.  As you can see it
gets tricky and that's why TCP exists because that's the kind of stuff it does
for you along with other stuff :)

> 
> As severel has said before, UDP does not guarantee delivery. My GUESS
> is that the Ada end writes to the socket faster than the Java end can
> consume it resulting in the OS' UDP buffer going full resulting in
> packet loss.
This is possible but please remember the java.net api is written as JNI/C code
shipped in .so's/.dlls so it should be relatively fast anyways.  Check the jdk
sources if you don't believe me.  What slows down the process in the JVM byte
code interpretation some where before and after the calls are made to java.net.

That said, I would suggest you use TCP sockets and not UDP sockets if you want
to have the packets delivered reliably.  

If you  would permit me to ask exactly what kind of application are you
writing?  

Cheers.