Name: nt126004 Date: 04/10/2002


FULL PRODUCT VERSION :
All current Java versions from 1.1.6 carry this problem.


A DESCRIPTION OF THE PROBLEM :
HTTP POST is a streaming protocol that can have
very long length streams sent over it. In my attempts to
format and send a multipart/form file upload, I found that
I was getting OutOfMemoryExceptions when sending
very large files (greated than 15MB). Bug number 4212479,
which was closed as 'Not a Bug' clearly states my problem
and the analysis, which is bogus in my opinion, doesn't
solve the problem.

What is needed is a way for HTTPURLConnection to turn
off the 'automatic Content-length' calculation that is being
done. I have already set my Content-length header and
want to simply stream the file over the socket. There is
no need for the HTTPURLConnection to buffer the entire
file in memory so that it can calculate the length of the
transmission. There should be a way to turn off this 'feature'
so that streaming transmissions can be made.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a URLConnection to a web site, and set up the code to
do an HTTP POST. Get the OutputStream from the connection
and write data into it. It will eventually fill up Java's heap and
the program will throw an OutOfMemoryException. If the HTTP
POST fits in memory, all is well. But if not, there's no way to
tell the URLConnection not to 'precalculate' the Content-Length
header, and so it must use a ByteArrayOutputStream which
provides limitations easily avoidable.



EXPECTED VERSUS ACTUAL BEHAVIOR :
I would expect c.getOutputStream() to return a stream
capable of handling any stream of data if the Content-Length
header has already been set. Instead it returns a stream
that can only handle a limited number of bytes (memory
limited).


ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.OutOfMemoryException

Stack trace wasn't available.


This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/*
 * TestPost.java
 *
 * Created on April 4, 2002, 4:42 PM
 */

import java.net.URL;
import java.net.URLConnection;
import java.net.HttpURLConnection;
import java.io.*;

public class TestPost {
    
    /** Creates a new instance of TestPost */
    public TestPost() {
    }

    public void test(String url) {
        try {
            URLConnection c = new URL(url).openConnection();
            c.setDoInput(true);
            c.setDoOutput(true);
            c.setUseCaches(false);
            if (c instanceof HttpURLConnection) {
                HttpURLConnection h = (HttpURLConnection)c;
                h.setRequestMethod("POST");
                h.setRequestProperty("Content-Length","100000000");
            }
            c.connect();
            OutputStream o = c.getOutputStream();
            if (o instanceof ByteArrayOutputStream) {
                throw new Exception("Inability to send large posts here.");
            }
            
        } catch (Throwable ex) {
            ex.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        String url = null;
        try {
            url = args[0];
        } catch (ArrayIndexOutOfBoundsException ex) {
            System.err.println("Usage: TestPost url");
            System.exit(0);
        }
        
        new TestPost().test(url);
    }
}


---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Use another HTTPClient implementation. There is no workaround within the
Sun JDK.
(Review ID: 145027)
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