UDP broadcasts and ServerSockets port confliction
myUDP broadcast port seems to randomly
conflict with myServerSockets.
some times its ok.
other times i getBindExceptions. it makes no
sense. now, here is the code:
byte[] message ="is there anyone out there".getBytes();
InetAddress addr = InetAddress.getByName("255.255.255.255");
DatagramPacket packet =new DatagramPacket(message, message.length, addr, 5511);
DatagramSocket dataSok =new DatagramSocket();
dataSok.send(packet);
and here is theServerSocket code:
ServerSocket servSok =new ServerSocket(5510);
here is the stack trace:
java.net.BindException: Address already in use: JVM_Bind
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.PlainSocketImpl.bind(Unknown Source)
at java.net.ServerSocket.bind(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at client.ServDiscovery$Registrar.run(ServDiscovery.java:161)
ialways use different ports.always.
yet, i get theseBindExceptions sometimes,
sometimes its fine.
note: i am usingEclipse, and if this is
anEclipse issue, i'm going to be very very
angry, upset, and sad.
i am so confused.
what is going on?
couldUDP packets be bouncing around my
LAN withTTL issues?
[1699 byte] By [
dew2hirooa] at [2007-11-27 3:27:58]
# 1
>
> i always use different ports. always.
> yet, i get these BindExceptions sometimes,
> sometimes its fine.
Err... different ports for what? If for the ServerSocket then why are you doing this? You do of course realize that other applications could be using some of these 'different ports'.
>
> note: i am using Eclipse, and if this
> is
> an Eclipse issue, i'm going to be very very
> angry, upset, and sad.
The standard response to problems people don't understand - blame the tools.
>
> i am so confused.
> what is going on?
> could UDP packets be bouncing around my
> LAN with TTL issues?
Eh!
How are UDP and your ServerSockets (which use TCP) going to clash?
# 2
> >
> > i always use different ports.
> > yet, i get these BindExceptions sometimes,
> > sometimes its fine.
>
> Err... different ports for what? If for the
> ServerSocket then why are you doing this? You do of
> course realize that other applications could be using
> some of these 'different ports'.
i change ports as soon as the phenonmenon starts.
a machine sends out a 1 to all UDP broadcast
on a LAN. then all machines listening on the port call
back to the machine by opening a Socket with
ServerSocket. ConnectionPools are then created.
> > what is going on?
> > could UDP packets be bouncing around my
> > LAN with TTL issues?
>
> Eh!
>
> How are UDP and your ServerSockets (which use TCP)
> going to clash?
if you look at the error report, it looks like the UDP broadcast
and ServerSocket might be trying to claim the same port on the
same machine.
i am going to run on jvms outside of the Eclipse abstraction.
and on a different LAN with different machines with different OS.
java is designed for networking, so java can't be the problem.
just consider this closed. its too strange.
# 4
> > if you look at the error report, it looks like the
> > UDP broadcast
> > and ServerSocket might be trying to claim
> the
> > same port on the
> > same machine.
> >
>
> They are allowed to use the same port because UDP
> ports and TCP ports are independent.
>
> P.S. Why do you open a ServerSocket on each machine?
its peer-to-peer.
all machines are clients and servers
anyway, this just can't be a java issue.
i should not have posted.
i'm off to a 100% new environment.
# 5
sabre150 and everyone that looked at this port, thanks for your reading.
i do not mean to discount that.
i think i got it.
i'm 70% sure its Eclipse.
the results vary depending on how i crash out
of the Console.
i don't think Eclipse does exactly this everytime
i re-run my application:
javac *java
java MainClient
but maybe it does?
yet, do to the abstraction, i can't say for sure.
i think Eclipse does a virtual reset.
i think this effected my
ClassLoader awhile back also.
Message was edited by:
dew2hiroo
