Erro ao executar um projeto GWT

Initializing AppEngine server

[WARN] failed com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@b0095d{/,/media/90B8-F5BF/workspace/SistemaComercial/war}: javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

[WARN] failed JettyContainerService$ApiProxyHandler@136d9d8: javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

[WARN] Error starting handlers

javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:131)

at org.mortbay.xml.XmlParser.setValidating(XmlParser.java:91)

at org.mortbay.xml.XmlParser.(XmlParser.java:83)

at org.mortbay.jetty.webapp.TagLibConfiguration.configureWebApp(TagLibConfiguration.java:210)

at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1247)

at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)

at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.jetty.Server.doStart(Server.java:224)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:185)

at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:149)

at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)

at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:108)

at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:431)

at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1053)

at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:795)

at com.google.gwt.dev.DevMode.main(DevMode.java:282)

[WARN] Nested in javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found:

java.lang.ClassNotFoundException: org.apache.xerces.jaxp.SAXParserFactoryImpl

at java.net.URLClassLoader$1.run(URLClassLoader.java:217)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:205)

at java.lang.ClassLoader.loadClass(ClassLoader.java:321)

at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:151)

at java.lang.ClassLoader.loadClass(ClassLoader.java:266)

at javax.xml.parsers.FactoryFinder.getProviderClass(FactoryFinder.java:109)

at javax.xml.parsers.FactoryFinder.newInstance(FactoryFinder.java:144)

at javax.xml.parsers.FactoryFinder.findJarServiceProvider(FactoryFinder.java:296)

at javax.xml.parsers.FactoryFinder.find(FactoryFinder.java:221)

at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:125)

at org.mortbay.xml.XmlParser.setValidating(XmlParser.java:91)

at org.mortbay.xml.XmlParser.(XmlParser.java:83)

at org.mortbay.jetty.webapp.TagLibConfiguration.configureWebApp(TagLibConfiguration.java:210)

at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1247)

at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)

at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.jetty.Server.doStart(Server.java:224)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:185)

at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:149)

at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)

at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:108)

at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:431)

at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1053)

at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:795)

at com.google.gwt.dev.DevMode.main(DevMode.java:282)

Initializing AppEngine server

[WARN] failed com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@130633a{/,/media/90B8-F5BF/workspace/SistemaComercial/war}: javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

[WARN] failed JettyContainerService$ApiProxyHandler@1c286e2: javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

[WARN] Error starting handlers

javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found

at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:131)

at org.mortbay.xml.XmlParser.setValidating(XmlParser.java:91)

at org.mortbay.xml.XmlParser.(XmlParser.java:83)

at org.mortbay.jetty.webapp.TagLibConfiguration.configureWebApp(TagLibConfiguration.java:210)

at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1247)

at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)

at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.jetty.Server.doStart(Server.java:224)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:185)

at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:149)

at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)

at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:108)

at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:421)

at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1035)

at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:783)

at com.google.gwt.dev.DevMode.main(DevMode.java:275)

[WARN] Nested in javax.xml.parsers.FactoryConfigurationError: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found:

java.lang.ClassNotFoundException: org.apache.xerces.jaxp.SAXParserFactoryImpl

at java.net.URLClassLoader$1.run(URLClassLoader.java:217)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:205)

at java.lang.ClassLoader.loadClass(ClassLoader.java:321)

at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:151)

at java.lang.ClassLoader.loadClass(ClassLoader.java:266)

at javax.xml.parsers.FactoryFinder.getProviderClass(FactoryFinder.java:109)

at javax.xml.parsers.FactoryFinder.newInstance(FactoryFinder.java:144)

at javax.xml.parsers.FactoryFinder.findJarServiceProvider(FactoryFinder.java:296)

at javax.xml.parsers.FactoryFinder.find(FactoryFinder.java:221)

at javax.xml.parsers.SAXParserFactory.newInstance(SAXParserFactory.java:125)

at org.mortbay.xml.XmlParser.setValidating(XmlParser.java:91)

at org.mortbay.xml.XmlParser.(XmlParser.java:83)

at org.mortbay.jetty.webapp.TagLibConfiguration.configureWebApp(TagLibConfiguration.java:210)

at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1247)

at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)

at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)

at org.mortbay.jetty.Server.doStart(Server.java:224)

at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:185)

at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:149)

at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)

at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:108)

at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:421)

at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1035)

at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:783)

at com.google.gwt.dev.DevMode.main(DevMode.java:275)