If I'm using .../computer/api/xml it I get this error:

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from
fulfilling this request.

exception

javax.servlet.ServletException: class org.jvnet.hudson.MemoryUsage doesn't have
@ExportedBean
org.kohsuke.stapler.Stapler.invoke(Stapler.java:449)
org.kohsuke.stapler.MetaClass$7.doDispatch(MetaClass.java:230)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:440)
org.kohsuke.stapler.MetaClass$7.doDispatch(MetaClass.java:230)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:440)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:361)
org.kohsuke.stapler.Stapler.service(Stapler.java:121)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:38)
hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:30)
hudson.security.HudsonFilter.doFilter(HudsonFilter.java:88)

root cause

org.kohsuke.stapler.export.NotExportableException: class
org.jvnet.hudson.MemoryUsage doesn't have @ExportedBean
org.kohsuke.stapler.export.Model.<init>(Model.java:44)
org.kohsuke.stapler.export.ModelBuilder.get(ModelBuilder.java:25)
org.kohsuke.stapler.export.Property.writeValue(Property.java:164)
org.kohsuke.stapler.export.Property.writeValue(Property.java:97)
org.kohsuke.stapler.export.Property.writeValue(Property.java:142)
org.kohsuke.stapler.export.Property.writeValue(Property.java:97)
org.kohsuke.stapler.export.Property.writeTo(Property.java:81)
org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:142)
org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:139)
org.kohsuke.stapler.export.Property.writeValue(Property.java:171)
org.kohsuke.stapler.export.Property.writeValue(Property.java:127)
org.kohsuke.stapler.export.Property.writeValue(Property.java:97)
org.kohsuke.stapler.export.Property.writeTo(Property.java:81)
org.kohsuke.stapler.export.Model.writeNestedObjectTo(Model.java:142)
org.kohsuke.stapler.export.Model.writeTo(Model.java:133)
org.kohsuke.stapler.ResponseImpl.serveExposedBean(ResponseImpl.java:108)
hudson.model.Api.doXml(Api.java:61)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:103)
org.kohsuke.stapler.Function.bindAndinvoke(Function.java:57)
org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:75)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:440)
org.kohsuke.stapler.MetaClass$7.doDispatch(MetaClass.java:230)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:440)
org.kohsuke.stapler.MetaClass$7.doDispatch(MetaClass.java:230)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:440)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:361)
org.kohsuke.stapler.Stapler.service(Stapler.java:121)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:38)
hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:30)
hudson.security.HudsonFilter.doFilter(HudsonFilter.java:88)

note The full stack trace of the root cause is available in the Apache
Tomcat/5.5.20 logs.
Apache Tomcat/5.5.20

Tested with version 234 and 235.

Thanks,
stefan