-
Bug
-
Resolution: Fixed
-
P3
-
1.2.0
-
kestrel
-
sparc
-
solaris_2.5
Name: mgC56079 Date: 12/10/98
A number of JCK tests (see justification) fail when loaded via CERN HTTP daemon
(however pass when loaded with Apache).
The reason is that AppletClassLoader throws ClassFormatError instead of
ClassNotFoundException if classes are loaded via CERN daemon.
Here is a simple test demonstrating the problem (the same nonexistent class is loaded
via different http daemons with different results):
========= Test1.java ===========
import java.net.*;
import sun.applet.AppletClassLoader;
public class Test1 {
public static void main(String argv[]) throws Exception {
// change these two lines as appropriate
URL cernURL = new URL("http://mars:8080/");
URL apacheURL = new URL("http://atos:80/");
MyClassLoader cl = new MyClassLoader(cernURL);
try {
cl.loadClass("some.nonexistent.Class");
}
catch (Throwable t) {
t.printStackTrace();
}
cl = new MyClassLoader(apacheURL);
try {
cl.loadClass("some.nonexistent.Class");
}
catch (Throwable t) {
t.printStackTrace();
}
}
}
class MyClassLoader extends AppletClassLoader {
public MyClassLoader(URL base) {
super(base);
}
}
====== output ======
(###@###.###)/home/gor/bugs: java Test1
java.lang.ClassFormatError: some/nonexistent/Class (Bad magic number)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Compiled Code)
at java.security.SecureClassLoader.defineClass(Compiled Code)
at sun.applet.AppletClassLoader.findClass(Compiled Code)
at java.lang.ClassLoader.loadClass(Compiled Code)
at sun.applet.AppletClassLoader.loadClass(Compiled Code)
at java.lang.ClassLoader.loadClass(Compiled Code)
at Test1.main(Compiled Code)
java.lang.ClassNotFoundException: java.io.IOException: Stream closed.
at java.net.PlainSocketImpl.available(Compiled Code)
at java.net.SocketInputStream.available(Compiled Code)
at java.io.BufferedInputStream.read(Compiled Code)
at java.io.FilterInputStream.read(Compiled Code)
at java.io.PushbackInputStream.read(Compiled Code)
at sun.applet.AppletClassLoader.getBytes(Compiled Code)
at sun.applet.AppletClassLoader.access$1(Compiled Code)
at sun.applet.AppletClassLoader$1.run(Compiled Code)
at java.security.AccessController.doPrivileged(Native Method)
at sun.applet.AppletClassLoader.findClass(Compiled Code)
at java.lang.ClassLoader.loadClass(Compiled Code)
at sun.applet.AppletClassLoader.loadClass(Compiled Code)
at java.lang.ClassLoader.loadClass(Compiled Code)
at Test1.main(Compiled Code)
=======================================
The reason for difference is a different responses from CERN and apache:
CERN specifies the Content-Length while Apache doesn't.
% telnet mars 8080
Trying 192.168.205.168...
Connected to mars.sparc.spb.su.
Escape character is '^]'.
GET /some/nonexistent/Class.class HTTP/1.0
HTTP/1.0 404 Not found - file doesn't exist or is read protected [even tried multi]
Server: CERN/3.0A
Date: Thu, 10 Dec 1998 12:11:11 GMT
Content-Type: text/html
Content-Length: 232
<HTML>
<HEAD>
<TITLE>Error</TITLE>
</HEAD>
<BODY>
<H1>Error 404</H1>
Not found - file doesn't exist or is read protected [even tried multi]
<P><HR><ADDRESS><A HREF="http://www.w3.org">CERN-HTTPD 3.0A</A></ADDRESS>
</BODY>
</HTML>
Connection closed by foreign host.
% telnet atos 80
Trying 192.168.205.37...
Connected to atos.
Escape character is '^]'.
GET /some/nonexistent/Class.class HTTP/1.0
HTTP/1.0 404 Not found
Date: Thu, 10 Dec 1998 12:16:29 GMT
Server: Apache/1.0.2
Content-type: text/html
<HEAD><TITLE>File Not found</TITLE></HEAD>
<BODY><H1>File Not found</H1>
The requested URL /some/nonexistent/Class.class was not found on this server.<P>
</BODY>
Connection closed by foreign host.
=========================
The problem here is that HttpURLConnection.getInputStream() will not throw
a FileNotFoundException if getContentLength() was called earlier.
This is a (correct) piece of code of AppletClassLoader:
private static byte[] getBytes(URL url) throws IOException {
URLConnection uc = url.openConnection();
int len = uc.getContentLength();
InputStream in = uc.getInputStream(); // !!!! SHOULD BUT WILL NOT THROW FileNotFoundException !!!!
byte[] b;
try {
if (len != -1)
... // !!!! do something (Apache)
else
... // !!!! do something different (CERN)
Here is a test demonstrating an inconsistent and buggy behaviour of HttpURLConnection.getInputStream().
======= Test.java =======
import java.net.*;
import java.io.*;
public class Test {
public static void main(String argv[]) throws Exception {
URL url=new URL("http://mars:8080/some/file");
URLConnection uc1=url.openConnection();
System.out.println("uc1.getContentLength()=" + uc1.getContentLength());
try {
InputStream is=uc1.getInputStream();
System.out.println("uc1: no exceptions");
}
catch (Exception e) {
System.out.println("uc1: got exception");
e.printStackTrace();
}
URLConnection uc2=url.openConnection();
try {
InputStream is=uc2.getInputStream();
System.out.println("uc2: no exceptions");
}
catch (Exception e) {
System.out.println("uc2: got exception");
e.printStackTrace();
}
}
}
====== output ======
% java Test
uc1.getContentLength()=232
uc1: no exceptions
uc2: got exception
java.io.FileNotFoundException: http://mars:8080/some/file
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Compiled Code)
at Test.main(Compiled Code)
======================================================================