Exception While using Adaptavist Bubbles Plugin

Dear Team,

I'm using Confluence 3.3.3 Version & Installed Community bubbles plugin adaptavist-plugin-bubbles-1.7.5.jar.
Installation was Successful but when I'm trying to use community bubbles it's throwing below exception in class file. Please Advise here.
Inline image 1

Cause

org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getCssheader' in class com.adaptavist.confluence.bubbles.userinterest.actions.SpaceWatchersAction threw exception com.thoughtworks.xstream.converters.ConversionException: Invalid final field java.util.Collections$SynchronizedMap.m ---- Debugging information ---- message : Invalid final field java.util.Collections$SynchronizedMap.m line number : 4 path : /java.util.Collections-SynchronizedMap/java.util.Collections-SynchronizedMap/default/m cause-message : Invalid final field java.util.Collections$SynchronizedMap.m class : java.util.Collections$SynchronizedMap cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException required-type : java.util.Collections$SynchronizedMap ------------------------------- at /templates/bubbles/userinterest/spacewatchers.vm[line 19, column 13]
at org.apache.velocity.runtime.parser.node.ASTMethod.handleInvocationException(ASTMethod.java:337)

caused by: com.thoughtworks.xstream.converters.ConversionException: Invalid final field java.util.Collections$SynchronizedMap.m ---- Debugging information ---- message : Invalid final field java.util.Collections$SynchronizedMap.m line number : 4 path : /java.util.Collections-SynchronizedMap/java.util.Collections-SynchronizedMap/default/m cause-message : Invalid final field java.util.Collections$SynchronizedMap.m class : java.util.Collections$SynchronizedMap cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException required-type : java.util.Collections$SynchronizedMap -------------------------------
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:45)

caused by: com.thoughtworks.xstream.converters.reflection.ObjectAccessException: Invalid final field java.util.Collections$SynchronizedMap.m
at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.validateFieldAccess(PureJavaReflectionProvider.java:150)

Stack Trace:[hide]

org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getCssheader' in  class com.adaptavist.confluence.bubbles.userinterest.actions.SpaceWatchersAction threw exception com.thoughtworks.xstream.converters.ConversionException: Invalid final field java.util.Collections$SynchronizedMap.m
---- Debugging information ----
message             : Invalid final field java.util.Collections$SynchronizedMap.m 
line number         : 4 
path                : /java.util.Collections-SynchronizedMap/java.util.Collections-SynchronizedMap/default/m 
cause-message       : Invalid final field java.util.Collections$SynchronizedMap.m 
class               : java.util.Collections$SynchronizedMap 
cause-exception     : com.thoughtworks.xstream.converters.reflection.ObjectAccessException 
required-type       : java.util.Collections$SynchronizedMap 
------------------------------- at /templates/bubbles/userinterest/spacewatchers.vm[line 19, column 13]
	at org.apache.velocity.runtime.parser.node.ASTMethod.handleInvocationException(ASTMethod.java:337)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:284)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:252)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:332)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at com.atlassian.confluence.setup.velocity.ApplyDecoratorDirective.render(ApplyDecoratorDirective.java:157)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at com.atlassian.confluence.setup.velocity.ApplyDecoratorDirective.render(ApplyDecoratorDirective.java:157)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:175)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336)
	at org.apache.velocity.Template.merge(Template.java:328)
	at org.apache.velocity.Template.merge(Template.java:235)
	at com.opensymphony.webwork.dispatcher.VelocityResult.doExecute(VelocityResult.java:91)
	at com.atlassian.xwork.results.ProfiledVelocityResult.doExecute(ProfiledVelocityResult.java:21)
	at com.opensymphony.webwork.dispatcher.WebWorkResultSupport.execute(WebWorkResultSupport.java:116)
	at com.opensymphony.xwork.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:263)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:187)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.intercept(DefaultWorkflowInterceptor.java:55)
	at com.atlassian.confluence.core.ConfluenceWorkflowInterceptor.intercept(ConfluenceWorkflowInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.xwork.interceptors.XsrfTokenInterceptor.intercept(XsrfTokenInterceptor.java:100)
	at com.atlassian.confluence.xwork.ConfluenceXsrfTokenInterceptor.intercept(ConfluenceXsrfTokenInterceptor.java:25)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.security.interceptors.CaptchaInterceptor.intercept(CaptchaInterceptor.java:46)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.util.LoggingContextInterceptor.intercept(LoggingContextInterceptor.java:49)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.core.CancellingInterceptor.intercept(CancellingInterceptor.java:23)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.security.websudo.WebSudoInterceptor.intercept(WebSudoInterceptor.java:73)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.security.actions.PermissionCheckInterceptor.intercept(PermissionCheckInterceptor.java:57)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.setup.webwork.BootstrapAwareInterceptor.intercept(BootstrapAwareInterceptor.java:26)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.user.actions.UserAwareInterceptor.intercept(UserAwareInterceptor.java:58)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.pages.actions.CommentAwareInterceptor.intercept(CommentAwareInterceptor.java:44)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.pages.actions.PageAwareInterceptor.intercept(PageAwareInterceptor.java:109)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.spaces.actions.SpaceAwareInterceptor.intercept(SpaceAwareInterceptor.java:68)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.core.actions.LastModifiedInterceptor.intercept(LastModifiedInterceptor.java:38)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.core.ConfluenceAutowireInterceptor.intercept(ConfluenceAutowireInterceptor.java:38)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeAndHandleExceptions(TransactionalInvocation.java:72)
	at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeInTransaction(TransactionalInvocation.java:59)
	at com.atlassian.xwork.interceptors.XWorkTransactionInterceptor.intercept(XWorkTransactionInterceptor.java:56)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.atlassian.confluence.xwork.SetupIncompleteInterceptor.intercept(SetupIncompleteInterceptor.java:40)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
	at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:115)
	at com.atlassian.confluence.servlet.ConfluenceServletDispatcher.serviceAction(ConfluenceServletDispatcher.java:53)
	at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:199)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.arsenale.plugins.lockpoint.LifecycleFilter.doFilter(SourceFile:53)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)
	at com.atlassian.confluence.util.profiling.ProfilingPageFilter.parsePage(ProfilingPageFilter.java:84)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:54)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.jmx.JmxFilter.doFilter(JmxFilter.java:106)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.core.filters.ServletContextThreadLocalFilter.doFilter(ServletContextThreadLocalFilter.java:19)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.util.LoggingContextFilter.doFilter(LoggingContextFilter.java:47)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.web.filter.ThreadLocalCacheFilter.doFilter(ThreadLocalCacheFilter.java:22)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.util.UserThreadLocalFilter.doFilter(UserThreadLocalFilter.java:44)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:219)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)
	at com.atlassian.confluence.util.AbstractBootstrapHotSwappingFilter.doFilter(AbstractBootstrapHotSwappingFilter.java:30)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.seraph.filter.BaseLoginFilter.doFilter(BaseLoginFilter.java:140)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:69)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.util.ClusterHeaderFilter.doFilter(ClusterHeaderFilter.java:34)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:72)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:170)
	at com.atlassian.spring.filter.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:29)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.util.ConfluenceErrorFilter.doFilter(ConfluenceErrorFilter.java:22)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.core.datetime.RequestTimeThreadLocalFilter.doFilter(RequestTimeThreadLocalFilter.java:35)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.util.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:25)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:81)
	at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
	at com.atlassian.confluence.extra.webdav.servlet.filter.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:43)
	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:44)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at com.atlassian.confluence.servlet.FourOhFourErrorLoggingFilter.doFilter(FourOhFourErrorLoggingFilter.java:65)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
	at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
	at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283)
	at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
	at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
	at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:889)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
	at java.lang.Thread.run(Unknown Source)
Caused by: com.thoughtworks.xstream.converters.ConversionException: Invalid final field java.util.Collections$SynchronizedMap.m
---- Debugging information ----
message             : Invalid final field java.util.Collections$SynchronizedMap.m 
line number         : 4 
path                : /java.util.Collections-SynchronizedMap/java.util.Collections-SynchronizedMap/default/m 
cause-message       : Invalid final field java.util.Collections$SynchronizedMap.m 
class               : java.util.Collections$SynchronizedMap 
cause-exception     : com.thoughtworks.xstream.converters.reflection.ObjectAccessException 
required-type       : java.util.Collections$SynchronizedMap 
-------------------------------
	at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:45)
	at com.thoughtworks.xstream.core.ReferenceByXPathUnmarshaller.convertAnother(ReferenceByXPathUnmarshaller.java:39)
	at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:99)
	at com.thoughtworks.xstream.core.ReferenceByXPathMarshallingStrategy.unmarshal(ReferenceByXPathMarshallingStrategy.java:12)
	at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:549)
	at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:537)
	at com.thoughtworks.xstream.XStream.fromXML(XStream.java:505)
	at com.thoughtworks.xstream.XStream.fromXML(XStream.java:496)
	at com.adaptavist.confluence.bubbles.communities.CommunityManager.loadMap(CommunityManager.java:363)
	at com.adaptavist.confluence.bubbles.communities.CommunityManager.initData(CommunityManager.java:316)
	at com.adaptavist.confluence.bubbles.communities.CommunityManager.getCommunityType(CommunityManager.java:473)
	at com.adaptavist.confluence.bubbles.customcss.CustomCSSManager.generateInclude(CustomCSSManager.java:145)
	at com.adaptavist.confluence.bubbles.customcss.CustomCSSManager.getActionCSSHeader(CustomCSSManager.java:183)
	at com.adaptavist.confluence.bubbles.BubblesSpaceAction.getCssheader(BubblesSpaceAction.java:32)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:389)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:378)
	at com.atlassian.confluence.velocity.introspection.UnboxingMethod.invoke(UnboxingMethod.java:31)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:270)
	... 194 more
Caused by: com.thoughtworks.xstream.converters.reflection.ObjectAccessException: Invalid final field java.util.Collections$SynchronizedMap.m
	at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.validateFieldAccess(PureJavaReflectionProvider.java:150)
	at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.writeField(PureJavaReflectionProvider.java:120)
	at com.thoughtworks.xstream.converters.reflection.SerializableConverter$2.defaultReadObject(SerializableConverter.java:331)
	at com.thoughtworks.xstream.converters.reflection.SerializableConverter.unmarshal(SerializableConverter.java:363)
	at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:38)
	... 215 more

5 answers

1 accepted

This widget could not be displayed.

It's worth noting that JDK 1.6 is the recommended version for confluence 3.3, so falling back to that may be worthwhile.

https://confluence.atlassian.com/display/CONF33/System+Requirements#SystemRequirements-Java

Dear alian,

Just to inform you I created one staging environment & tested with below with same version & below Java Specs, Bubbles is working fine, here also it's using Java 7 Only. Please Advise.

<th colspan="2" width="90%">Java Runtime Environment</th>
Operating System Linux 2.6.32-358.el6.x86_64
OS Architecture amd64
Application Server Apache Tomcat/6.0.26
Servlet Version 2.5
Java Version 1.7.0_09-icedtea
Java Vendor Oracle Corporation
JVM Version 1.7
JVM Vendor Oracle Corporation
JVM Implementation Version 23.2-b09
Java Runtime OpenJDK Runtime Environment
Java VM OpenJDK 64-Bit Server VM
Java Runtime Arguments -Djava.util.logging.config.file=/opt/atlassian/confluence-3.3.3-std/conf/logging.properties -Xms256m -Xmx512m -XX:MaxPermSize=256m -Djava.awt.headless=true -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/atlassian/confluence-3.3.3-std/endorsed -Dcatalina.base=/opt/atlassian/confluence-3.3.3-std -Dcatalina.home=/opt/atlassian/confluence-3.3.3-std -Djava.io.tmpdir=/opt/atlassian/confluence-3.3.3-std/temp

Regards

Amber

Dear Team,

Kindly confirm if we are going to downgrade java from 1.7 to 1.6 for confluence it will affect the confluence or not.

Regards

Amber

Dear Alain,

Please not I've craeted same environment like production site in staging machine & installed same version & Java Runtime & checked bubbles was workin fine. Not Sure if Java 6 will help to solve the problem. Can you plesae advise if any other thing need to be checked As with same Java installed in Productin it's working fine in Staging.

<th colspan="2" width="90%">Java Runtime Environment</th>
Operating System Linux 2.6.32-358.el6.x86_64
OS Architecture amd64
Application Server Apache Tomcat/6.0.26
Servlet Version 2.5
Java Version 1.7.0
Java Vendor Oracle Corporation
JVM Version 1.7
JVM Vendor Oracle Corporation
JVM Implementation Version 21.0-b17
Java Runtime Java(TM) SE Runtime Environment
Java VM Java HotSpot(TM) 64-Bit Server VM
Java Runtime Arguments -Djava.util.logging.config.file=/opt/atlassian/confluence-3.3.3-std/conf/logging.properties -Xms256m -Xmx512m -XX:MaxPermSize=256m -Djava.awt.headless=true -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/atlassian/confluence-3.3.3-std/endorsed -Dcatalina.base=/opt/atlassian/confluence-3.3.3-std -Dcatalina.home=/opt/atlassian/confluence-3.3.3-std -Djava.io.tmpdir=/opt/atlassian/confluence-3.3.3-std/temp

Seems not be JAVA Version Issue, Checked with JAVA 6 Also facing same issue, Created one staging environment & tested with both JAVA 6 & JAVA 7 Community bubble was working fine.

It Might be possible if plugin clash issue with previosly installed plugin, Can you please help here.

Thanks

Amber

This widget could not be displayed.

Are you using Java7 or the openJDK?

We've noticed this happen with a few plugins and it appears to be related to the version of XStream that Atlassian include with the base distribution - they are using version 1.1.1 which is not compatible with the JVM you are using.

We have found that by filtering out the dependancy provided by Confluence and replacing it with the more recent 1.4.2 then this issue can be worked around, however unfortunately this process has yet to be applied to bubbles.

Can you tell me if you are using the openJDK (so far all reports we have seen of this issue are openJDK based) or the Sun JVM?

Dear Alian,

Please find required details below & suggest for the solution.

Java Runtime Environment

Operating SystemLinux 2.6.18-274.12.1.el5

OS Architectureamd64

Application ServerApache Tomcat/6.0.14

Servlet Version2.5

Java Version1.7.0_02

Java VendorOracle Corporation

JVM Version1.7

JVM VendorOracle Corporation

JVM Implementation Version22.0-b10

Java RuntimeJava(TM) SE Runtime Environment

Java VMJava HotSpot(TM) 64-Bit Server VM

Java Runtime Arguments-Xms256m -Xmx3G -XX:+UseParallelOldGC -XX:MaxPermSize=512m -Djava.awt.headless=true -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.util.logging.config.file=/opt/atlassian/confluence-3.3-std/conf/logging.properties -Djava.endorsed.dirs=/opt/atlassian/confluence-3.3-std/endorsed -Dcatalina.base=/opt/atlassian/confluence-3.3-std -Dcatalina.home=/opt/atlassian/confluence-3.3-std -Djava.io.tmpdir=/opt/atlassian/confluence-3.3-std/temp

Thanks in Advance

Amber

This widget could not be displayed.

Thanks for that ... so it looks like the problem is a generic Java7 issue :(

This widget could not be displayed.

Team Downgrading Java to 1.6 Solve the Issue. Thanks a lot.

Regards

Amber

This widget could not be displayed.

JAVA 1.6 Sort the Issue.

Thanks

Amber

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