NoClassDefFoundError caused by Atlassian Streams

2014-01-20 08:52:32,870 INFO [http-bio-8085-exec-23] [AccessLogFilter] mchai GET https://jira.bamboo.atlassian.com/plugins/servlet/streams?local=true&use-accept-lang=true&maxResults=10 1062728kb

Caused by: java.lang.NoClassDefFoundError: org/apache/xerces/dom/DocumentImpl
	at org.owasp.validator.html.scan.AntiSamyDOMScanner.<init>(AntiSamyDOMScanner.java:76)
	at org.owasp.validator.html.AntiSamy.scan(AntiSamy.java:107)
	at com.atlassian.streams.internal.feed.FeedContentSanitizerImpl.sanitize(FeedContentSanitizerImpl.java:55)
	at sun.reflect.GeneratedMethodAccessor1758.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
	at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:58)
	at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.invoke(ServiceInvoker.java:62)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:131)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:119)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invokeUnprivileged(ServiceTCCLInterceptor.java:56)
	at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invoke(ServiceTCCLInterceptor.java:39)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.osgi.service.importer.support.LocalBundleContextAdvice.invoke(LocalBundleContextAdvice.java:59)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:131)
	at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:119)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at com.sun.proxy.$Proxy785.sanitize(Unknown Source)
	at com.atlassian.streams.internal.atom.abdera.AbderaAtomFeedRenderer$AtomFeedBuilder.getAtomEntry(AbderaAtomFeedRenderer.java:240)
	at com.atlassian.streams.internal.atom.abdera.AbderaAtomFeedRenderer$AtomFeedBuilder.build(AbderaAtomFeedRenderer.java:170)
	at com.atlassian.streams.internal.atom.abdera.AbderaAtomFeedRenderer.writeFeed(AbderaAtomFeedRenderer.java:106)
	at com.atlassian.streams.internal.servlet.StreamsActivityServlet.doGet(StreamsActivityServlet.java:91)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at com.atlassian.plugin.servlet.DelegatingPluginServlet.service(DelegatingPluginServlet.java:42)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at com.atlassian.plugin.servlet.ServletModuleContainerServlet.service(ServletModuleContainerServlet.java:52)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	... 143 more