Mailing-List: contact tomcat-user-help@jakarta.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
Received-SPF: pass (hermes.apache.org: domain of
 alexandre.akoulov@citigroup.com designates 199.67.203.181 as permitted
 sender)
content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="----_=_NextPart_001_01C546D4.FA17F8D6"
Subject: RE: Problem with the classloader in jakarta-tomcat-5.0.28 - cannot
 add a jar file to class repository
Date: Fri, 22 Apr 2005 10:48:19 +1000
Message-ID: <1F78B75C252B574FBC551990AE8A836702EE105A@exsymb02.aus.nsroot.net>
Thread-Topic: Problem with the classloader in jakarta-tomcat-5.0.28 - cannot
 add a jar file to class repository
Thread-Index: AcVGTDgaQOh5BfPITDCSQNNgbypw+gAGC2YQABtO6NA=
From: "Akoulov, Alexandre [IT]" <alexandre.akoulov@citigroup.com>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>

------_=_NextPart_001_01C546D4.FA17F8D6
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Thanks Chuck for your reply.

I still think it is a bug!!!=20

Please try the following: add a jar file (eg, foo/bar.jar) as a class =
repository in the catalina.properties and then use one of the classes =
from this jar file in one the servlets - will get a =
ClassNotFoundException.

I've attached ClassLoaderFactoryTest.java and =
ClassLoaderFactoryWithTheFix.java. Please try to run the test - one of =
the tests will fail, refer to the place where it fails and read the =
comments.


Kind regards,

Alex.


-----Original Message-----
From: Caldarale, Charles R [mailto:Chuck.Caldarale@unisys.com]
Sent: Thursday, 21 April 2005 9:27 PM
To: Tomcat Users List
Subject: RE: Problem with the classloader in jakarta-tomcat-5.0.28 -
cannot add a jar file to class repository


> From: Akoulov, Alexandre [IT] [mailto:alexandre.akoulov@citigroup.com]

> Subject: Problem with the classloader in=20
> jakarta-tomcat-5.0.28 - cannot add a jar file to class repository
>=20
> ClassLoaderFactory#createClassLoader(File unpacked[], File=20
> packed[], URL urls[], ClassLoader parent) is the actual=20
> method that creates class loaders. The very first argument to=20
> this method contains jar files or directories ( that is where=20
> the name "unpacked" comes from ).=20

>From what I can tell, it's the _second_ argument that should contain
.jar files; the first is for directories only.

 - Chuck


THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY
MATERIAL and is thus for use only by the intended recipient. If you
received this in error, please contact the sender and delete the e-mail
and its attachments from all computers.

---------------------------------------------------------------------
To unsubscribe, e-mail: tomcat-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tomcat-user-help@jakarta.apache.org


-----Original Message-----
From: Akoulov, Alexandre [IT]=20
Sent: Thursday, 21 April 2005 6:29 PM
To: tomcat-user@jakarta.apache.org
Subject: Problem with the classloader in jakarta-tomcat-5.0.28 - cannot
add a jar file to class repository


Hi all,

I'd greatly appreciate your thoughts on the following issue (and the =
proposed solution ):


When adding a jar file (eg, "foo/bar.jar") to the class loader's =
repository it treats as a directory and therefore it cannot load any =
classes from this jar. The following explains why it happens.
=09
org.apache.catalina.startup.ClassLoaderFactory is responsible for =
creating class loader instances. Each instance is of =
org.apache.catalina.loader.StandardClassLoader type, which in its turn =
extends java.net.URLClassLoader:
-------------------------------------------------------------------------=
----
			public class StandardClassLoader extends URLClassLoader
-------------------------------------------------------------------------=
----
=09
ClassLoaderFactory#createClassLoader(File unpacked[], File packed[], URL =
urls[], ClassLoader parent) is the actual method that creates class =
loaders. The very first argument to this method contains jar files or =
directories ( that is where the name "unpacked" comes from ).=20
=09
ClassLoaderFactory#createClassLoader method adds File.separator to the =
end of the jar file path ( file.getCanonicalPath() + File.separator ) =
when constructing a URL instance to represent a jar file and then adds a =
string representation of a newly created URL to its list of repositories =
( list.add(url.toString()) ) :
-------------------------------------------------------------------------=
----
			if (unpacked !=3D null) {
            	for (int i =3D 0; i < unpacked.length; i++)  {
	                File file =3D unpacked[i];
	                if (!file.exists() || !file.canRead())
	                    continue;
	                if (debug >=3D 1)
	                    log("  Including directory or JAR "=20
	                        + file.getAbsolutePath());
	                URL url =3D new URL("file", null,
	                                  file.getCanonicalPath() + =
File.separator);
	                list.add(url.toString());
	            }
	        }
-------------------------------------------------------------------------=
----
	       =20
For instance, if "unpacked"	argument contains =
'/home/aa/lib/velocity.jar' then a URL object is =
'file:/home/aa/lib/velocity.jar/' - a forward slash / (which is a Unix =
file separator) has been added to the url.
=09
After ClassLoaderFactory#createClassLoader adds all repositories to its =
repository list it converts this list to array and constructs =
StandardClassLoader with it:
=09
-------------------------------------------------------------------------=
----
			String array[] =3D (String[]) list.toArray(new String[list.size()]);
	        StandardClassLoader classLoader =3D null;
	        if (parent =3D=3D null)
	            classLoader =3D new StandardClassLoader(array);
-------------------------------------------------------------------------=
----
	   =20
StandardClassLoader( String[] ) constructor converts each repository =
found in the given array argument to a URL object:
-------------------------------------------------------------------------=
----
		    protected static URL[] convert(String input[], =
URLStreamHandlerFactory factory) {
		    	.....
		    	url[i] =3D new URL(null, input[i], streamHandler);
		    	.....
		    }
-------------------------------------------------------------------------=
----
                                  =20
For instance, if the repositories array of String type contains =
'file:/home/aa/lib/velocity.jar/' then a URL object is =
'file:/home/aa/lib/velocity.jar/'. If the repository holds a path on =
Windows machine then the URL object would have all backslashes  replaced =
all  with forward slashes ( URL object crated with new URL(null, =
"file:I:\lib\velocity.jar\", streamHandler) would have =
"file:I:/lib/velocity.jar/" string representation ).
   =20
Once StandardClassLoader( String[] ) converts repository array of a =
String type into a URL type it calls its super constructor, which in =
fact is a URLClassLoader( URL[] ).
   =20
However, the contract for URLClassLoader( URL[] ) constructor indicates =
that "Any URL that ends with a '/' is assumed to refer to a directory. " =
and therefore a jar file gets ignored by the loader.
   =20
For instance, if the repositories array contains =
'file:/home/aa/lib/velocity.jar/' url object the URLClassLoader( URL[] ) =
constructor treats this url as a directory and therefore a jar file is =
never properly loaded.
   =20
   =20
Therefore, a File.separator that got added to a jar file in =
ClassLoaderFactory#createClassLoader method made it invalid because the =
actual class loader assumes that this jar file is a directory.
   =20
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
   =20
Proposed solution
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=


ClassLoaderFactory#createClassLoader(File unpacked[], File packed[], URL =
urls[], ClassLoader parent) is to be modified so that it does not add =
File.separator to the end of jar files found in the unpacked argument:
    =20
-------------------------------------------------------------------------=
----
			if (unpacked !=3D null) {
            	for (int i =3D 0; i < unpacked.length; i++)  {
	                File file =3D unpacked[i];
	                if (!file.exists() || !file.canRead())
	                    continue;
	                if (debug >=3D 1)
	                    log("  Including directory or JAR "=20
	                        + file.getAbsolutePath());
	               =20
	                // THE FIX
	                StringBuffer filePath =3D new =
StringBuffer(file.getCanonicalPath());
	                if ( file.isDirectory() ) {=20
	                	// Only add a file separator if a file represents a =
directory
	                	filePath.append(File.separator);
	                }
	                               =20
	                URL url =3D new URL("file", null, filePath.toString());
	                list.add(url.toString());
	            }
	        }=09
-------------------------------------------------------------------------=
----
		=09
=09


Kind regards,

Alex.
=09

---------------------------------------------------------------------
To unsubscribe, e-mail: tomcat-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tomcat-user-help@jakarta.apache.org


------_=_NextPart_001_01C546D4.FA17F8D6
Content-Type: text/plain; charset=us-ascii

---------------------------------------------------------------------
To unsubscribe, e-mail: tomcat-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tomcat-user-help@jakarta.apache.org
------_=_NextPart_001_01C546D4.FA17F8D6--