Tomcat 6 customized Realm

I'm trying to write my own Realm to authenticate my users. I have written a class extending org.apache.catalina.realm.RealmBase, compiled to a .jar file and put it in the /lib library. Then I added this to server.xml:

<Realm className="wstest.tomcat.security.MyRealm"
             resourceName="myrealm"/>

Tomcat doesn't seem to "see" my new jar... When I start Tomcat I get:

ERROR main org.apache.commons.digester.Digester - Begin event threw exception
java.lang.ClassNotFoundException: wstest.tomcat.security.MyRealm
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
    at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:205)
    at org.apache.tomcat.util.digester.Rule.begin(Rule.java:153)
    at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1356)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:501)
    at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:179)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1343)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2755)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configurat开发者_C百科ion.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1642)
    at org.apache.catalina.startup.Catalina.load(Catalina.java:526)
    at org.apache.catalina.startup.Catalina.load(Catalina.java:560)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:261)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)

Which /lib folder have you used? The one in your WebProject or the one in tomcat? I'm a tomcat greenhorn myself but as far as I know you should place your JAR in the latter one.

server.xml is loaded before the webapps. Therefore tomcat needs to find your Realm implementation class before it gets to load your application JAR files. Place the JAR in tomcat/lib and that should fix the problem.

You also need to be aware of one gotcha: don't log anything in the Realm constructor. The containerLog field is not set in there so you'll get a nasty NPE. loadInternal() sets the containerLog.