The Confluence JSON-RPC API does not work with some built-in Confluence Remote API methods

The JSON-RPC plugin is unable to expose some parts of the Confluence Remote API.
For example, the following request fails:

https://extranet.atlassian.com/rpc/json-rpc/confluenceservice-v2/addComment Body: [

{"pageId": "1997209807", "content": "this is my comment"}

]

With this exception response:

{"jsonrpc":"2.0","id":null,"error":

{"message":"The application was unable to serve your request: java.lang.IllegalArgumentException: interface com.atlassian.confluence.content.service.comment.CreateCommentCommand is not visible from class loader","data":"java.lang.IllegalArgumentException: interface com.atlassian.confluence.content.service.comment.CreateCommentCommand is not visible from class loader\njava.lang.IllegalArgumentException: interface com.atlassian.confluence.content.service.comment.CreateCommentCommand is not visible from class loader\n\tat java.lang.reflect.Proxy.getProxyClass0(Proxy.java:484)\n\tat java.lang.reflect.Proxy.newProxyInstance(Proxy.java:713)\n\tat org.springframework.aop.framework.JdkDynamicAopProxy.getProxy(JdkDynamicAopProxy.java:117)\n\tat org.springframework.aop.framework.JdkDynamicAopProxy.getProxy(JdkDynamicAopProxy.java:108)\n\tat org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:97)\n\tat com.atlassian.confluence.util.AopUtils.createAdvisedProxy(AopUtils.java:56)\n\tat com.atlassian.confluence.spring.aop.AdviseReturnedValueAdvice.invoke(AdviseReturnedValueAdvice.java:34)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)\n\tat org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)\n\tat com.sun.proxy.$Proxy109.newCreateCommentCommand(Unknown Source)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)\n\tat sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.lang.reflect.Method.invoke(Method.java:601)\n\tat org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)\n\tat org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)\n\tat org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)\n\tat com.sun.proxy.$Proxy110.newCreateCommentCommand(Unknown Source)\n\tat com.atlassian.confluence.rpc.soap.services.PagesSoapService.addComment(PagesSoapService.java:165)\n\tat com.atlassian.confluence.rpc.soap.XhtmlSoapService.addComment(XhtmlSoapService.java:303)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)\n\tat sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.lang.reflect.Method.invoke(Method.java:601)\n\tat org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)\n\tat com.atlassian.spring.interceptors.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:16)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)\n\tat org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)\n\tat org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)\n\tat com.sun.proxy.$Proxy1502.addComment(Unknown Source)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)\n\tat sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.lang.reflect.Method.invoke(Method.java:601)\n\tat com.atlassian.rpc.jsonrpc.SoapModuleMethodMapper.call(SoapModuleMethodMapper.java:120)\n\tat com.atlassian.voorhees.JsonRpcHandler.executeMethod(JsonRpcHandler.java:235)\n\tat com.atlassian.voorhees.JsonRpcHandler.process(JsonRpcHandler.java:83)\n\tat com.atlassian.rpc.jsonrpc.JsonRpcFilter.doFilter(JsonRpcFilter.java:76)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.plugin.remotable.plugin.module.permission.ApiScopingFilter.doFilter(ApiScopingFilter.java:62)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.core.filters.ServletContextThreadLocalFilter.doFilter(ServletContextThreadLocalFilter.java:21)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.util.LoggingContextFilter.doFilter(LoggingContextFilter.java:40)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.util.UserNameHeaderFilter.doFilter(UserNameHeaderFilter.java:26)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:211)\n\tat com.atlassian.confluence.web.filter.ConfluenceSecurityFilter.doFilter(ConfluenceSecurityFilter.java:28)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.web.filter.ThreadLocalCacheFilter.doFilter(ThreadLocalCacheFilter.java:22)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)\n\tat com.atlassian.confluence.util.AbstractBootstrapHotSwappingFilter.doFilter(AbstractBootstrapHotSwappingFilter.java:30)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.seraph.filter.BaseLoginFilter.doFilter(BaseLoginFilter.java:150)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:55)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.util.ClusterHeaderFilter.doFilter(ClusterHeaderFilter.java:37)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:99)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:74)\n\tat com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.plugin.remotable.plugin.module.oauth.OAuth2LOFilter.doFilter(OAuth2LOFilter.java:70)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.confluence.extras.upgrader.SessionWrappingFilter.doFilter(SessionWrappingFilter.java:22)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.plugin.remotable.host.common.service.http.bigpipe.BigPipeRequestIdFilter.doFilter(BigPipeRequestIdFilter.java:35)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.prettyurls.filter.PrettyUrlsCombinedMatchDispatcherFilter.doFilter(PrettyUrlsCombinedMatchDispatcherFilter.java:61)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)\n\tat com.atlassian.confluence.extra.webdav.servlet.filter.ReverseProxyFilter.doFilter(ReverseProxyFilter.java:427)\n\tat com.atlassian.confluence.extra.webdav.servlet.filter.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:34)\n\tat com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)\n\tat com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)\n\tat com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.web.filter.validateparam.RequestParamValidationFilter.doFilter(RequestParamValidationFilter.java:58)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.web.filter.TranslationModeFilter.doFilter(TranslationModeFilter.java:43)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.plugin.servlet.filter.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:71)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.web.filter.LanguageExtractionFilter.doFilter(LanguageExtractionFilter.java:53)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.util.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:25)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.web.filter.DebugFilter.doFilter(DebugFilter.java:44)\n\tat com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:44)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat com.atlassian.confluence.servlet.FourOhFourErrorLoggingFilter.doFilter(FourOhFourErrorLoggingFilter.java:65)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)\n\tat org.apache.catalina.ha.tcp.ReplicationValve.invoke(ReplicationValve.java:347)\n\tat org.apache.catalina.ha.session.JvmRouteBinderValve.invoke(JvmRouteBinderValve.java:227)\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)\n\tat org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)\n\tat org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)\n\tat org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)\n\tat java.lang.Thread.run(Thread.java:722)\n","code":500}

}