title: GWT Compiler Error: Element 'extend-property' contains unexpected attribute 'fallback-value'
body: <p>When I'm trying to run my app on server I have the following errors:</p>
  
  <pre><code>Error:GWT Compiler: Element 'extend-property' beginning on line 27 contains unexpected attribute 'fallback-value'
  Error:GWT Compiler: Failure while parsing XML
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.DefaultSchema.onUnexpectedAttribute(DefaultSchema.java:68)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.Schema.onUnexpectedAttribute(Schema.java:80)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.startElement(ReflectiveParser.java:224)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:506)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:182)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1303)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2717)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:489)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:327)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.access$100(ReflectiveParser.java:48)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser.parse(ReflectiveParser.java:398)
  Error:GWT Compiler: at com.google.gwt.dev.cfg.ModuleDefLoader.nestedLoad(ModuleDefLoader.java:257)
  Error:GWT Compiler: at com.google.gwt.dev.cfg.ModuleDefSchema$BodySchema.__inherits_begin(ModuleDefSchema.java:354)
  Error:GWT Compiler: at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  Error:GWT Compiler: at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
  Error:GWT Compiler: at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  Error:GWT Compiler: at java.lang.reflect.Method.invoke(Method.java:601)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.HandlerMethod.invokeBegin(HandlerMethod.java:223)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.startElement(ReflectiveParser.java:270)
  Error:GWT Compiler: at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.emptyElement(XMLDTDValidator.java:766)
  Error:GWT Compiler: at com.google.gwt.dev.cfg.ModuleDefLoader$1.load(ModuleDefLoader.java:169)
  Error:GWT Compiler: at com.google.gwt.dev.cfg.ModuleDefLoader.doLoadModule(ModuleDefLoader.java:283)
  Error:GWT Compiler: at com.google.gwt.dev.cfg.ModuleDefLoader.loadFromClassPath(ModuleDefLoader.java:141)
  Error:GWT Compiler: at com.google.gwt.dev.Compiler.run(Compiler.java:184)
  Error:GWT Compiler: at com.google.gwt.dev.Compiler$1.run(Compiler.java:152)
  Error:GWT Compiler: at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:87)
  Error:GWT Compiler: at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:81)
  Error:GWT Compiler: at com.google.gwt.dev.Compiler.main(Compiler.java:159)
  Error:GWT Compiler: Unexpected error while processing XML
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.ReflectiveParser$Impl.parse(ReflectiveParser.java:351)
  Error:GWT Compiler: Unexpected exception while processing element 'inherits'
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.DefaultSchema.onHandlerException(DefaultSchema.java:56)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.Schema.onHandlerException(Schema.java:66)
  Error:GWT Compiler: at com.google.gwt.dev.util.xml.HandlerMethod.invokeBegin(HandlerMethod.java:233)
  </code></pre>
  
  <p>I guess these all are caused by maven, so here is pom.xml:</p>
  
  <pre><code>&lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"&gt;
    &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
  
    &lt;groupId&gt;com.messagedna.dlp&lt;/groupId&gt;
    &lt;artifactId&gt;DLPServer&lt;/artifactId&gt;
    &lt;version&gt;1.0-SNAPSHOT&lt;/version&gt;
    &lt;packaging&gt;jar&lt;/packaging&gt;
  
    &lt;name&gt;DLPServer&lt;/name&gt;
    &lt;url&gt;http://maven.apache.org&lt;/url&gt;
  
    &lt;properties&gt;
      &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
    &lt;/properties&gt;
  
    &lt;dependencies&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
            &lt;artifactId&gt;gwt-servlet&lt;/artifactId&gt;
            &lt;version&gt;2.0.3&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;com.google.gwt&lt;/groupId&gt;
            &lt;artifactId&gt;gwt-user&lt;/artifactId&gt;
            &lt;version&gt;2.0.3&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;com.extjs&lt;/groupId&gt;
            &lt;artifactId&gt;gxt&lt;/artifactId&gt;
            &lt;version&gt;2.2.0&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;commons-configuration&lt;/groupId&gt;
            &lt;artifactId&gt;commons-configuration&lt;/artifactId&gt;
            &lt;version&gt;1.9&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;javax.mail&lt;/groupId&gt;
            &lt;artifactId&gt;mail&lt;/artifactId&gt;
            &lt;version&gt;1.4.5&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;org.apache.james&lt;/groupId&gt;
            &lt;artifactId&gt;apache-mime4j&lt;/artifactId&gt;
            &lt;version&gt;0.6.1&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;org.apache.tika&lt;/groupId&gt;
            &lt;artifactId&gt;tika-parsers&lt;/artifactId&gt;
            &lt;version&gt;1.2&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;net.freeutils.jtnef&lt;/groupId&gt;
            &lt;artifactId&gt;tnef&lt;/artifactId&gt;
            &lt;version&gt;1.5.0&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;com.messagedna-archive.mimeparser&lt;/groupId&gt;
            &lt;artifactId&gt;MimeParser&lt;/artifactId&gt;
            &lt;version&gt;1.0&lt;/version&gt;
        &lt;/dependency&gt;
  
        &lt;dependency&gt;
            &lt;groupId&gt;com.rabbitmq&lt;/groupId&gt;
            &lt;artifactId&gt;amqp-client&lt;/artifactId&gt;
            &lt;version&gt;3.0.4&lt;/version&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
            &lt;groupId&gt;commons-lang&lt;/groupId&gt;
            &lt;artifactId&gt;commons-lang&lt;/artifactId&gt;
            &lt;version&gt;2.3&lt;/version&gt;
        &lt;/dependency&gt;
  
        &lt;dependency&gt;
            &lt;groupId&gt;junit&lt;/groupId&gt;
            &lt;artifactId&gt;junit&lt;/artifactId&gt;
            &lt;version&gt;4.10&lt;/version&gt;
            &lt;scope&gt;test&lt;/scope&gt;
        &lt;/dependency&gt;
    &lt;/dependencies&gt;
    &lt;build&gt;
          &lt;outputDirectory&gt;war/WEB-INF/classes&lt;/outputDirectory&gt;
          &lt;plugins&gt;
            &lt;plugin&gt;
                &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
                &lt;artifactId&gt;gwt-maven-plugin&lt;/artifactId&gt;
                &lt;version&gt;1.2&lt;/version&gt;
                &lt;executions&gt;
                    &lt;execution&gt;
                        &lt;goals&gt;
                            &lt;goal&gt;compile&lt;/goal&gt;
                            &lt;goal&gt;generateAsync&lt;/goal&gt;
                            &lt;goal&gt;test&lt;/goal&gt;
                        &lt;/goals&gt;
                    &lt;/execution&gt;
                &lt;/executions&gt;
                &lt;configuration&gt;
                    &lt;runTarget&gt;Main.html&lt;/runTarget&gt;
                    &lt;style&gt;OBFUSCATED&lt;/style&gt;
                    &lt;extraJvmArgs&gt;-Xmx1024m -Xss1024k&lt;/extraJvmArgs&gt;
                    &lt;webappDirectory&gt;war&lt;/webappDirectory&gt;
                &lt;/configuration&gt;
            &lt;/plugin&gt;
  
            &lt;plugin&gt;
                &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
                &lt;artifactId&gt;maven-war-plugin&lt;/artifactId&gt;
                &lt;version&gt;2.1.1&lt;/version&gt;
                &lt;configuration&gt;
                    &lt;webappDirectory&gt;war&lt;/webappDirectory&gt;
                    &lt;warSourceExcludes&gt;.gwt-tmp/**&lt;/warSourceExcludes&gt;
                &lt;/configuration&gt;
            &lt;/plugin&gt;
              &lt;plugin&gt;
                  &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
                  &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
                  &lt;version&gt;3.0&lt;/version&gt;
                  &lt;configuration&gt;
                      &lt;source&gt;1.6&lt;/source&gt;
                      &lt;target&gt;1.6&lt;/target&gt;
                  &lt;/configuration&gt;
              &lt;/plugin&gt;
          &lt;/plugins&gt;
    &lt;/build&gt;
  &lt;/project&gt;
  </code></pre>
  
  <p>whenever I've trying to search in google I didn't figured out the solution, there were questions partly like this but they are without any solution.</p>
  
  <p>So, please, have a look at this and I'll be very greatful if you can suggest any way to solve this problems.</p>