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Opening & closing of ServerSocket

Posted on 1997-04-07
2
Medium Priority
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Last Modified: 2006-11-17
I have a program like:

//*********
.....
ServerSocket s1;

s1=new ServerSocket(21);
....
 //invoke a thread to accept multiple connections
new somethread(s1, ..).start();
....
....

public boolean action(Event e, Object arg)
{
if(somethingIsTrue)
 {
  try   {
         System.out.println("going to close ServerSocket");        
         s1.close();      // the program hangs here
         System.out.println("ServerSocket closed");        
       
        }
        catch(Exception e) {     System.out.println("ServerSocket
excpt");   }
 }
.......
}
...
//*******************


I face two problems while running this problem:

1. I am not able to close ServerSocket. It doesn't even throw any
exceptions. The program simply hangs there. Of course, I am able to
close the ServerSocket s1, if I accept connections without invoking
a thread like the one shown above, i.e

 //invoke a thread to accept multiple connections
new somethread(s1, ..).start();

In Java, it appears you cannot shutdown a server and restart it
without quitting the entire program.

2. If a daemon is already on the port 21, any attempt to open
ServerSocket
on the same port should throw some exceptions but nothing happens in
Java.

I use JDK1.0.2 under win95 but if it is fixed in JDK1.1 can I simply
replace java.net package in CLASSES.ZIP in JDK1.0.2 with the java.net
package
in JDK1.1.

Has anyone come across this problem?

Thanks
Parameshwar Babu


--
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Question by:pbabu
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2 Comments
 
LVL 1

Expert Comment

by:trof
ID: 1219475
Tell us more about your VM implementation. Is it pure java.exe or JView (j++) or what ?
0
 

Accepted Solution

by:
tlandry earned 600 total points
ID: 1219476
Phabu,

Failure of server sockets to close is a known bug in JDK1.02,
at least for Win95/NT.  Simply using the JDK1.1 class files
may not be enought to fix the situation.  You may need
to use the JDK1.1 VM as well, provided Javasoft fixed this
bug in 1.1.

Hope this helps,

Ted
0

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