Networking

own problems and a lot of overkill.

Does it possible to have two thread running at the same time which reads from the same

socket. If a message is received, does both threads then receive it?

Answer: Two threads can read data from the same socket input stream, but they WON T each

get copies of the same data. They ll each get separate parts of the message.

Q: how can I get an IP Adress in the class InetAdress? The constructor is private, so I can't

use it. I want to call the method getName () to get the domain name out of an IP Adress.

Answer:  It is not necessary to construct something : )

Just do it like this:

for example: String hostname = InetAddress.getLocalHost().getHostName();

 I m converting an old java client/server program which is based on raw byte stream heavily

into new one which requires utilizing object streams. But if I open input/output object streams

on both sides this blocks system and won t proceed...

Hi,

I m converting an old java client/server program which is based on raw byte stream heavily

into new one which requires utilizing object streams. But if I open input/output object streams

on both side this blocks system and won t proceed.

ObjectInputStream in = new ObjectInputStream(socket.getInputStream());

ObjectOutputStream out = new

ObjectOutputStream(socket.getOutputStream());

Answer:  Upon opening the ObjectInputStream, the constructor blocks to read a header from

the stream (doing who knows what). Now, what happens is, both your client and server open

the InputStream... and happily wait forever for the other side to send them the header they

want. Deadlock guaranteed!

The solution is simple: open the ObjectOutputStream first on at least one side, but better on

both sides (usually, symmetry == good). Problem solved

:)

You are trying to keep two streams going at once independently, right.

That means you need at least two threads at each end.

Are there classes available to read and write to an RS 232 port or does this require using

native code?

Answer:  See the Java Communications API.

 Q: Is there a System property that ll tell me the (TCP/IP) machine name? If not, how do

you go about it?

I need to display all the machine s TCP/IP addresses to the user. This requires a call to

InetAddress.getAllByName(), which requires the machine name. You *can t* pass null or

"localhost" to this method. Well, you can pass "localhost", but that only gets you the localhost

addy itself 

127.0.0.1. Not useful.

Answer:  Try this: Working that out, I tried

String hostname = InetAddress.getLocalHost().getHostName();

System.out.println(hostname);

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