java - Sometimes HttpURLConnection.getInputStream executes too slowly

Question

We have next code.
Sometimes we should wait 10-20-40 seconds on the last line.
What can be the problem?

Java 1.4

URL url = ...;
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.connect();
OutputStream out = conn.getOutputStream();
ObjectOutputStream outStream = new ObjectOutputStream(out);
try
{
   outStream.writeObject(objArray);
}
finally
{
   outStream.close();
}

InputStream input = conn.getInputStream();

UPDATED:
Next code fixes the problem IN ECLIPSE.
But it still DOES NOT WORK via Java WebStart:(

HttpURLConnection conn = (HttpURLConnection) url.openConnection();  
conn.setDoInput(true);  
conn.setDoOutput(true);  
conn.setUseCaches(false);  
System.setProperty("http.keepAlive", "false");  //<---------------
conn.connect();  

But why?

UPDATED one more time!
Bug was fixed! :)
We worked with connections not in one class but in two.
And there is following line in the second class:

URL url = ...  
HttpURLConnection conn = (HttpURLConnection) url.openConnection();  
conn.setRequestProperty("Content-Length", "1000");  //<------------
conn.connect();  

Note: setRequestProperty("Content-Length", "1000") is root cause of the problem.

Answer 1

'We had a similar issue which is caused by buggy keep-alive in old Java. Add this before connect to see if it helps,

conn.setRequestProperty("Connection", "close");

or

System.setProperty("http.keepAlive", "false");