[kaffe] ClassLoader isn't working like I expected
Tom Epperly
tepperly at llnl.gov
Tue May 13 08:20:01 PDT 2003
I have some DTDs for XML parsing that I add to the jar file with the rest of
my code. It's convenient to put them in the jar file; otherwise, I need to
know what directory they are installed in.
My code uses getClass().getClassLoader().getResourceAsStream() to get an
InputStream for the DTD files. This approach works with Sun's JVM, and it
doesn't work with the Kaffe that I installed from Debian x86 unstable
distribution. I've included a simple test case below to demonstrate the issue.
If there is a better (portable between Kaffe and Sun's JVM) way for me to
get an InputStream for the DTD files in my JAR file, I would love to hear
it. Please Cc me on replies.
Thanks in advance,
Tom
To demonstrate this issue, you need two files in directories as follows:
LoaderProblem/Test.java
dtd/SIDL.dtd
//----begin Test.java----
package LoaderProblem;
import java.io.InputStream;
public class Test {
public static void main(String [] args) {
try {
Test t = new Test();
ClassLoader loader = t.getClass().getClassLoader();
InputStream in = loader.getResourceAsStream("dtd/SIDL.dtd");
if (in != null) {
byte [] buffer = new byte[256];
int len;
while ((len = in.read(buffer, 0, 255)) >= 0) {
System.out.write(buffer, 0, len);
}
}
}
catch (java.io.IOException ioe) {
ioe.printStackTrace();
}
}
}
//-----end Test.java----
dtd/SIDL.dtd can be any short text file. For example,
//----start SIDL.dtd
Hello world
//----end SIDL.dtd
% javac LoaderProblem/Test.java
% jar cf lp.jar LoaderProblem/Test.class dtd/SIDL.dtd
% /usr/local/j2sdk1.4.1_02/bin/java -classpath lp.jar LoaderProblem.Test
Hello world
% kaffe -addclasspath lp.jar LoaderProblem.Test
java.lang.NullPointerException
at LoaderProblem.Test.main(Test.java:20)
% kaffe -version
Kaffe Virtual Machine
Copyright (c) 1996-2002 Kaffe.org project contributors (please see
the source code for a full list of contributors). All rights reservced.
Portions Copyright (c) 1996-2002 Transvirtual Technologies, Inc.
The Kaffe virtual machine is free software, licensed under the terms of
the GNU General Public License. Kaffe.org is a an independent, free software
community project, not directly affiliated with Transvirtual Technologies,
Inc. Kaffe is a Trademark of Transvirtual Technologies, Inc. Kaffe comes
with ABSOLUTELY NO WARRANTY.
Engine: Just-in-time v3 Version: 1.0.7 Java Version: 1.1
% uname -a
Linux driftcreek 2.4.20 #11 Tue Jan 21 08:44:00 PST 2003 i686 unknown
unknown GNU/Linux
% dpkg --list kaffe
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name Version Description
+++-==============-==============-============================================
ii kaffe 1.0.7-3 A JVM to run Java bytecode
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