Override jboss-jmx.jar in 3.2.5?

[ctday]

There is a bug in the javax.management.monitor.Monitor class that prevents me from using StringMonitors. I know how to fix the code, but I'm looking at a production environment where I want to deploy the change with a minimum of effort. In particular, I don't want to get into building and maintaining my own version of Jboss 3.2.5. Is there any way through configuration - properties files, environment variables, etc. - to direct a booting Jboss to pick up my fixed version of Monitor before it loads jboss-jmx.jar? jboss.patch.dir sounds promising, but I don't know how to get it to function. Thanks.

[starksm64]

The patchdir option adds the jar to the start of the bootstrap classpath and can be used to override the microkernel jars including jmx. Post the patch to jira.
http://jira.jboss.com/jira/secure/JBJMX

[ctday]

Patch posted to JIRA, but the patchdir option has me stumped. The fix works, since if I replace the class directly in $JBOSS_HOME/lib/jboss-jmx.jar, my program works correctly. However, if i make a jar with the corrected class, put the jar in a patches directory and use the --patchdir option, the program still throws the ClassCastException => the override isn't happening. Nevertheless, the boot.log shows that the Boot url list contains both my patches directory and my patch jar file and that a UnifiedClassLoader is created for the patch jar file.

Actually, I don't understand how the override is supposed to work. The UCL of the patch jar has the boot URL class loader as its parent. This parent loader is explicitly given the $JBOSS_HOME/lib/jboss-jmx.jar as a URL to work from. If the UCL defers to its parent, doesn't that mean that the $JBOSS_HOME/lib/jboss-jmx.jar will always win out over a class with the same name in the patch jar? Any help would be appreciated. Thanks.

[starksm64]

Ok, I thought the patchdir was added to the bootclasspath. The -L library option adds jars to the bootclasspath which could be used to override /lib jars.

[ctday]

Well, the -L and -C options will override some ${JBOSS_HOME}/lib jars, but not xercesImpl.jar, xml-apis.jar, xalan.jar, jboss-jmx.jar, dom4j.jar, gnu-regexp.jar, or concurrent.jar. These are all explicitly fed to the ServerLoader by Main _before_ anything from the command line. So again, the override of jboss-jmx.jar fails.

[starksm64]

Ok. Another option will have to be added then.

[starksm64]

I added another -B|-bootlib option to prepend jars to the bootclasspath. The 3.2 branch code diff against 3.2.5 is shown below.

[starksm@lamia jboss]$ cvs diff -r JBoss_3_2_5 Main.java
Index: Main.java
===================================================================
RCS file: /cvsroot/jboss/jboss-system/src/main/org/jboss/Main.java,v
retrieving revision 1.17.2.13
retrieving revision 1.17.2.16
diff -r1.17.2.13 -r1.17.2.16
12a13
> import java.lang.reflect.Method;
13a15
> import java.net.URLDecoder;
25d26
< import org.jboss.system.server.ServerLoader;
26a28
> import org.jboss.system.server.ServerLoader;
44c46
< * @version $Revision: 1.17.2.13 $
---
> * @version $Revision: 1.17.2.16 $
52c54
< private String jmxLibs = "jboss-jmx.jar,dom4j.jar,gnu-regexp.jar";
---
> private String jmxLibs = "jboss-jmx.jar,dom4j.jar,jaxen.jar,gnu-regexp.jar";
55a58,62
> /** Extra jars added to the start of the boot classpath. This can be used
> to override jboss /lib boot classes
> */
> private List bootLibraries = new LinkedList();
>
98c105
< path = java.net.URLDecoder.decode(path);
---
> path = urlDecode(path);
116a124,129
> // Add any extra libraries
> for (int i = 0; i < bootLibraries.size(); i++)
> {
> loader.addLibrary((String)bootLibraries.get(i));
> }
>
194a208
> new LongOpt("bootlib", LongOpt.REQUIRED_ARGUMENT, null, 'B'),
236a251
> System.out.println(" -B, --bootlib=<filename> Add an extra library to the front bootclasspth");
340a356,360
> case 'B':
> arg = getopt.getOptarg();
> bootLibraries.add(arg);
> break;
>
383a404,424
> * Decode the path depending upon whether we have java1.4 or java1.3 installed
> *
> * @param path the path to decode
> * @return the decoded path
> * @throws Exception for any error
> */
> private String urlDecode(String path) throws Exception
> {
> Method decode;
> try
> {
> decode = URLDecoder.class.getMethod("decode", new Class[] { String.class, String.class });
> return (String) decode.invoke(null, new Object[] { path, "UTF-8" });
> }
> catch (NoSuchMethodException e)
> {
> return URLDecoder.decode(path);
> }
> }
>
> /**

[ctday]

Thanks. I will give it a try.

[ctday]

Almost. The problem with your patch, from my viewpoint, is that it uses ServerLoader.addLibrary(). This forces the javax-management-monitor-Monitor-patch.jar patch to jboss-jmx.jar to reside in the same directory as the rest of the boot JARs. That means that I either add my javax-management-monitor-Monitor-patch.jar patch JAR to the ${JBOSS_HOME}/lib directory, which means I'm directly fiddling with the Jboss distribution and I want to treat that as read-only, or I move all of ${JBOSS_HOME}/lib over to someplace under my own control, which means I am over-treating the correction. It seems that if the patch to Main uses ServerLoader.addURL() instead, I can keep the bulk of the boot JARs in ${JBOSS_HOME}/lib and still have the Monitor patch in a directory under my control. I include a proposed alternative patch to org.jboss.Main below based on the 3.2.5 version.

--- /cygdrive/c/jboss-3.2.5-src/system/src/main/org/jboss/Main.java 2004-06-15 11:44:28.000000000 -0700
+++ /cygdrive/c/eclipse/workspaceExo/Jboss-patches/org/jboss/Main.java 2004-12-30 12:48:25.956603200 -0800
@@ -10,7 +10,9 @@
 package org.jboss;

 import java.io.File;
+import java.lang.reflect.Method;
 import java.net.URL;
+import java.net.URLDecoder;
 import java.net.MalformedURLException;
 import java.util.Properties;
 import java.util.List;
@@ -22,8 +24,8 @@

 import org.jboss.system.server.Server;
 import org.jboss.system.server.ServerConfig;
-import org.jboss.system.server.ServerLoader;
 import org.jboss.system.server.ServerConfigUtil;
+import org.jboss.system.server.ServerLoader;

 /**
 * Provides a command line interface to start the JBoss server.
@@ -41,7 +43,7 @@
 * @author <a href="mailto:[e-mail]">Marc Fleury</a>
 * @author <a href="mailto:[e-mail]">Jason Dillon</a>
 * @author <a href="mailto:[e-mail]">Adrian Brock</a>
- * @version $Revision: 1.17.2.13 $
+ * @version $Revision: 1.17.2.16 $
 */
 public class Main
 {
@@ -49,10 +51,15 @@
 private String jaxpLibs = "xercesImpl.jar,xml-apis.jar,xalan.jar";

 /** The JMX library to use. */
- private String jmxLibs = "jboss-jmx.jar,dom4j.jar,gnu-regexp.jar";
+ private String jmxLibs = "jboss-jmx.jar,dom4j.jar,jaxen.jar,gnu-regexp.jar";

 private String concurrentLib = "concurrent.jar";

+ /** Extra jars added to the start of the boot classpath. This can be used
+ to override jboss /lib boot classes
+ */
+ private List bootUrls = new LinkedList();
+
 /** Extra libraries to load the server with .*/
 private List extraLibraries = new LinkedList();

@@ -95,7 +102,7 @@
 * this path through the decoder so that is JBoss starts in a path with
 * spaces we don't come crashing down.
 */
- path = java.net.URLDecoder.decode(path);
+ path = urlDecode(path);
 File runJar = new File(path);
 File homeFile = runJar.getParentFile().getParentFile();
 homeDir = homeFile.getCanonicalPath();
@@ -114,6 +121,12 @@
 // Load the server instance
 ServerLoader loader = new ServerLoader(props);

+ // Add any extra libraries
+ for (int i = 0; i < bootUrls.size(); i++)
+ {
+ loader.addURL((URL) bootUrls.get(i));
+ }
+
 // Add JAXP and JMX libs
 loader.addLibraries(jaxpLibs);
 loader.addLibraries(jmxLibs);
@@ -192,6 +205,7 @@
 new LongOpt("configuration", LongOpt.REQUIRED_ARGUMENT, null, 'c'),
 new LongOpt("version", LongOpt.NO_ARGUMENT, null, 'V'),
 new LongOpt("jaxp", LongOpt.REQUIRED_ARGUMENT, null, 'j'),
+ new LongOpt("bootlib", LongOpt.REQUIRED_ARGUMENT, null, 'B'),
 new LongOpt("library", LongOpt.REQUIRED_ARGUMENT, null, 'L'),
 new LongOpt("classpath", LongOpt.REQUIRED_ARGUMENT, null, 'C'),
 new LongOpt("properties", LongOpt.REQUIRED_ARGUMENT, null, 'P'),
@@ -234,6 +248,7 @@
 System.out.println(" -n, --netboot=<url> Boot from net with the given url as base");
 System.out.println(" -c, --configuration=<name> Set the server configuration name");
 System.out.println(" -j, --jaxp=<type> Set the JAXP impl type (ie. crimson)");
+ System.out.println(" -B, --bootlib=<filename> Add an extra library to the front bootclasspth");
 System.out.println(" -L, --library=<filename> Add an extra library to the loaders classpath");
 System.out.println(" -C, --classpath=<url> Add an extra url to the loaders classpath");
 System.out.println(" -P, --properties=<url> Load system properties from the given url");
@@ -338,6 +353,11 @@
 break;
 }

+ case 'B':
+ arg = getopt.getOptarg();
+ bootUrls.add(makeURL(arg));
+ break;
+
 case 'L':
 arg = getopt.getOptarg();
 extraLibraries.add(arg);
@@ -381,6 +401,27 @@
 }

 /**
+ * Decode the path depending upon whether we have java1.4 or java1.3 installed
+ *
+ * @param path the path to decode
+ * @return the decoded path
+ * @throws Exception for any error
+ */
+ private String urlDecode(String path) throws Exception
+ {
+ Method decode;
+ try
+ {
+ decode = URLDecoder.class.getMethod("decode", new Class[] { String.class, String.class });
+ return (String) decode.invoke(null, new Object[] { path, "UTF-8" });
+ }
+ catch (NoSuchMethodException e)
+ {
+ return URLDecoder.decode(path);
+ }
+ }
+
+ /**
 * This is where the magic begins.
 *
 * <P>Starts up inside of a "jboss" thread group to allow better

[starksm64]

Ok, I created a feature request for this issue. I believe the patchdir behavior should simply be updated to what you describe as its currently not a useful option.

http://jira.jboss.com/jira/browse/JBAS-1265