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Bug
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Resolution: Duplicate
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P4
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None
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1.4.0
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x86
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windows_95
Name: nt126004 Date: 01/15/2002
FULL PRODUCT VERSION :
java version "1.4.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta3-b84)
Java HotSpot(TM) Client VM (build 1.4.0-beta3-b84, mixed mode)
FULL OPERATING SYSTEM VERSION :
Windows 95. [Version 4.00.1111]
ADDITIONAL OPERATING SYSTEMS :
Solaris 2.8
A DESCRIPTION OF THE PROBLEM :
If an InputStream from a URLConnection as provided by 2 supplied testcases is read then a NullPointer Exception is thrown on close(). This only happens if a page is read that has an incorrect content-length in the header. In comparison Java 1.1 exhibits correct behavior.
REGRESSION. Last worked in version 1.1.8
STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1.Start any servlet engine, any JSDK with BugServlet installed.
2.Run Test
3.check console output of Test
EXPECTED VERSUS ACTUAL BEHAVIOR :
In the console window, you should see:
java.version = 1.4.0-beta3
reading
reading
reading
After while() loop
After close()
ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.version = 1.4.0-beta3
reading
After while() loop
Exception in thread "main" java.lang.NullPointerException
at sun.net.www.http.KeepAliveStream.close(Unknown Source)
at java.io.FilterInputStream.close(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.close(Unknown
Source)
at sun.nio.cs.StreamDecoder$CharsetSD.implClose(Unknown Source)
at sun.nio.cs.StreamDecoder.close(Unknown Source)
at java.io.InputStreamReader.close(Unknown Source)
at java.io.BufferedReader.close(Unknown Source)
at Test.main(Test.java:144)
This bug can be reproduced always.
---------- BEGIN SOURCE ----------
First the test servlet BugServlet that provides the ouptput
which
is input for this testcase:
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class BugServlet extends HttpServlet {
public void service (HttpServletRequest req,
HttpServletResponse res)
throws ServletException, IOException
{
String
outputString="<HTML><BODY><H1>Hello</H1></BODY></HTML>";
res.setContentType("text/html");
res.setContentLength(outputString.length()+5);
PrintWriter out = res.getWriter ();
out.print(outputString);
out.flush();
out.close();
}//End service()
}//End class BugServlet
The above servlet creates an output whose content-length
header is set incorrectly
(5 bytes too long in this case).
However, if the corresponding URL is opened from within a
web browser,
the expected output "Hello" is displayed.
Next the class Test that demonstrates the error.
With Java 1.4.0-beta3, it throws NullPointerexception.
With Java 1.3, it freezes on startup with 100% CPU utilization.
With Java 1.1, it runs ok (takes a little while).
The URL:
http://localhost/servlet/BugServlet
assumes that a servlet engine is running on the local
machine on port 80.
Please feel free to adapt it to your requirements.
The URL
http://www.google.com/addurl?q=http%3A%2F%2Fwww.javasoft.com
is provided as a REAL WORLD example (subject to change).
It causes the same lock-up bahaviour for apparently the same
reason.
The error is particularily critical for Java based web
crawler type of applications.
*/
import java.net.*;
import java.io.*;
public class URLTest {
static public void main(String args[]) {
System.out.println("java.version =
"+System.getProperty("java.version"));
try{
//Only "get" methot supported on this URL
//The following google URL still fails on 2001-12-30
URL submURLObj = new
URL("http://www.google.com/addurl?q=http%3A%2F%2Fwww.javasoft.com");
//The following servlet URL always fails with the supplied
test servlet
// URL submURLObj = new
URL("http://localhost/servlet/BugServlet");
URLConnection conn = submURLObj.openConnection();
BufferedReader buf_reader = new BufferedReader(
new
InputStreamReader(conn.getInputStream()));
StringBuffer returnBuf = new StringBuffer();
String str = null;
while( (str=buf_reader.readLine()) != null){
System.out.println("reading");
}
System.out.println("After while() loop");
// NullPointerException on close() below:
buf_reader.close();
System.out.println("After close()");
}catch(MalformedURLException e1){
e1.printStackTrace();
}
catch(IOException e2){
e2.printStackTrace();
}
System.exit(0);
}//End main()
}//End class Test
---------- END SOURCE ----------
CUSTOMER WORKAROUND :
Catch NullPointerException on close().
There may be side effects of this bug (memory leaks etc)
that I am not aware of and which are not covered by this
workaround
(Review ID: 137813)
======================================================================
- duplicates
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- Closed
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