I would like to use the org.apache.commons.validator.GenericValidator class in a view class of my GWT web app. I have read that I have to implicitely tell that I intend to use this external library. I thought adding the next line into my App.gwt.xml would work.

<inherits name='org.apache.commons.validator.GenericValidator'/>

I get the next error:

    Loading inherited module 'org.apache.commons.validator.GenericValidator'
       [ERROR] Unable to find 'org/apache/commons/validator/GenericValidator.gwt.xml' on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?
    [ERROR] Line 13: Unexpected exception while processing element 'inherits'
    com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
at com.google.gwt.dev.cfg.ModuleDefLoader.nestedLoad(ModuleDefLoader.java:239)
    at com.google.gwt.dev.cfg.ModuleDefSchema$BodySchema.__inherits_begin(ModuleDefSchema.java:354)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.gwt.dev.util.xml.HandlerMethod.invokeBegin(HandlerMethod.java:223)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.startElement(ReflectiveParser.java:270)
    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:1339)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2747)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:327)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.access$100(ReflectiveParser.java:48)
    at com.google.gwt.dev.util.xml.ReflectiveParser.parse(ReflectiveParser.java:398)
    at com.google.gwt.dev.cfg.ModuleDefLoader.nestedLoad(ModuleDefLoader.java:257)
    at com.google.gwt.dev.cfg.ModuleDefLoader$1.load(ModuleDefLoader.java:169)
    at com.google.gwt.dev.cfg.ModuleDefLoader.doLoadModule(ModuleDefLoader.java:283)
    at com.google.gwt.dev.cfg.ModuleDefLoader.loadFromClassPath(ModuleDefLoader.java:141)
    at com.google.gwt.dev.Compiler.run(Compiler.java:184)
    at com.google.gwt.dev.Compiler$1.run(Compiler.java:152)
    at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:87)
    at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:81)
    at com.google.gwt.dev.Compiler.main(Compiler.java:159)
[ERROR] Failure while parsing XML
com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
    at com.google.gwt.dev.util.xml.DefaultSchema.onHandlerException(DefaultSchema.java:56)
    at com.google.gwt.dev.util.xml.Schema.onHandlerException(Schema.java:66)
    at com.google.gwt.dev.util.xml.Schema.onHandlerException(Schema.java:66)
    at com.google.gwt.dev.util.xml.HandlerMethod.invokeBegin(HandlerMethod.java:233)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.startElement(ReflectiveParser.java:270)
    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:1339)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2747)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:327)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.access$100(ReflectiveParser.java:48)
    at com.google.gwt.dev.util.xml.ReflectiveParser.parse(ReflectiveParser.java:398)
    at com.google.gwt.dev.cfg.ModuleDefLoader.nestedLoad(ModuleDefLoader.java:257)
    at com.google.gwt.dev.cfg.ModuleDefLoader$1.load(ModuleDefLoader.java:169)
    at com.google.gwt.dev.cfg.ModuleDefLoader.doLoadModule(ModuleDefLoader.java:283)
    at com.google.gwt.dev.cfg.ModuleDefLoader.loadFromClassPath(ModuleDefLoader.java:141)
    at com.google.gwt.dev.Compiler.run(Compiler.java:184)
    at com.google.gwt.dev.Compiler$1.run(Compiler.java:152)
    at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:87)
    at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:81)
    at com.google.gwt.dev.Compiler.main(Compiler.java:159)
[ERROR] Unexpected error while processing XML
com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:351)
    at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.access$100(ReflectiveParser.java:48)
    at com.google.gwt.dev.util.xml.ReflectiveParser.parse(ReflectiveParser.java:398)
    at com.google.gwt.dev.cfg.ModuleDefLoader.nestedLoad(ModuleDefLoader.java:257)
    at com.google.gwt.dev.cfg.ModuleDefLoader$1.load(ModuleDefLoader.java:169)
    at com.google.gwt.dev.cfg.ModuleDefLoader.doLoadModule(ModuleDefLoader.java:283)
    at com.google.gwt.dev.cfg.ModuleDefLoader.loadFromClassPath(ModuleDefLoader.java:141)
    at com.google.gwt.dev.Compiler.run(Compiler.java:184)
    at com.google.gwt.dev.Compiler$1.run(Compiler.java:152)
    at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:87)
    at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:81)
    at com.google.gwt.dev.Compiler.main(Compiler.java:159)

I have commons.validator-1.3.1.jar in war/WEB-INF/lib

I am using eclipse with Google Plugin.

Anyone knows how it works?