NPE in restrictions user/group lookup when searching for group which name matches existing user name

go to Add a Page / Restrictions, Click Edit, Choose Users, click Groups and enter "admin" and click search.

Expected result:
list of groups that start with "admin" or an error "there are no 'admin' groups"

Actual result:

Cause:
java.lang.NullPointerException
at com.opensymphony.user.provider.hibernate.HibernateAccessProvider.listUsersInGroup(HibernateAccessProvider.java:152)

Stack Trace: [hide]

java.lang.NullPointerException
at com.opensymphony.user.provider.hibernate.HibernateAccessProvider.listUsersInGroup(HibernateAccessProvider.java:152)
at bucket.user.providers.ChainedAccessProvider.listUsersInGroup(ChainedAccessProvider.java:49)
at com.atlassian.user.impl.osuser.OSUGroupManager.getMemberNames(OSUGroupManager.java:180)
at com.atlassian.user.impl.delegation.DelegatingListGroupManager.getMemberNames(DelegatingListGroupManager.java:93)
at bucket.user.DefaultUserAccessor.getMemberNames(DefaultUserAccessor.java:580)
at sun.reflect.GeneratedMethodAccessor1995.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:284)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:155)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:122)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:56)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:174)
at $Proxy16.getMemberNames(Unknown Source)
at com.atlassian.confluence.user.actions.UserPickerAction.execute(UserPickerAction.java:64)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)
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:39)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
at com.atlassian.confluence.core.ConfluenceValidationInterceptor.intercept(ConfluenceValidationInterceptor.java:16)
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:48)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.security.actions.PermissionCheckInterceptor.intercept(PermissionCheckInterceptor.java:47)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.pages.actions.PageAwareInterceptor.intercept(PageAwareInterceptor.java:114)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.spaces.actions.SpaceAwareInterceptor.intercept(SpaceAwareInterceptor.java:67)
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:39)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
at com.atlassian.confluence.core.ConfluenceAutowireInterceptor.intercept(ConfluenceAutowireInterceptor.java:25)
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.XWorkTransactionInterceptor.intercept(XWorkTransactionInterceptor.java:98)
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.opensymphony.webwork.dispatcher.ServletDispatcher.serviceAction(ServletDispatcher.java:229)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:199)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:917)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:391)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:297)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:117)
at com.atlassian.confluence.util.profiling.ProfilingPageFilter.parsePage(ProfilingPageFilter.java:137)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.core.filters.ServletContextThreadLocalFilter.doFilter(ServletContextThreadLocalFilter.java:21)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.confluence.util.LoggingContextFilter.doFilter(LoggingContextFilter.java:46)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.confluence.util.UserThreadLocalFilter.doFilter(UserThreadLocalFilter.java:44)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:159)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.confluence.util.ClusterHeaderFilter.doFilter(ClusterHeaderFilter.java:35)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.johnson.filters.JohnsonFilter.doFilter(JohnsonFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:172)
at com.atlassian.spring.filter.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:29)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:122)
at com.atlassian.core.filters.ProfilingAndErrorFilter.doFilter(ProfilingAndErrorFilter.java:27)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.confluence.util.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:25)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.core.filters.gzip.GzipFilter.doFilter(GzipFilter.java:61)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.atlassian.core.filters.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:37)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at com.sun.dse.wikis.auth.SsoFilter.doFilter(SsoFilter.java:136)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:270)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:241)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:182)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:160)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at com.sun.webserver.connector.nsapi.NSAPIProcessor.process(NSAPIProcessor.java:149)
at com.sun.webserver.connector.nsapi.NSAPIConnector.service(NSAPIConnector.java:995)
Referer URL: http://wikis.sun.com/users/userpicker.action?searchType=searchByUserDetails&fullnameTerm=q&emailTerm=&usernameTerm=&operator=match+all&onPopupSubmit=addViewPermissionsUsers

Build Information:
system.uptime: 4 days, 23 hours, 16 minutes, 10 seconds
system.version: 2.5.2
build.number: 807

Server Information:
Application Server: Sun Java System Web Server/7.0
Servlet Version: 2.4
Database Dialect: com.atlassian.hibernate.dialect.MySQLDialect
Database Driver Name: com.mysql.jdbc.Driver
Database Driver Version: 5.0

Memory Information:
total.memory: 169 MB
free.memory: 63 MB
used.memory: 106 MB

System Information:
system.date: Tuesday, 26 Jun 2007
system.time: 17:17:52
system.favourite.colour: Myrtle
java.version: 1.5.0_09
java.vendor: Sun Microsystems Inc.
jvm.version: 1.0
jvm.vendor: Sun Microsystems Inc.
jvm.implementation.version: 1.5.0_09-b03
java.runtime: Java(TM) 2 Runtime Environment, Standard Edition
java.vm: Java HotSpot(TM) Server VM
user.timezone: US/Pacific
operating.system: SunOS 5.10
os.architecture: sparc
fs.encoding: ISO8859-1

Cluster Information:
Name: wikis
Description: TangosolClusterInformation: wikis, listening on 228.244.92.247:32365
Members:
Member(Id=1, Timestamp=2007-06-21 18:01:47.259, Address=72.5.126.79:8088, MachineId=12366)

Enabled Plugins:
Page Tabs (confluence.sections.page, Version: 1.0)
Basic Macros (confluence.macros.basic, Version: 1.3)
Core Listeners (confluence.listeners.core, Version: 1.3)
Dashboard Macros (confluence.macros.dashboard, Version: 1.3)
User Listener (confluence.extra.userlister, Version: 1.2)
Chart Plugin (confluence.extra.chart, Version: 1.8)
Live Search Macros (confluence.extra.livesearch, Version: 1.6)
Information Macros (confluence.extra.information, Version: 0.2)
Global Labels Sections (confluence.sections.labels, Version: 1.0)
Page View Links (confluence.sections.page.actions, Version: 1.0)
JIRA Macros (confluence.extra.jira, Version: 1.6)
Page Operations (confluence.sections.page.operations, Version: 1.0)
Layout Macros (confluence.extra.layout, Version: 0.2)
WebDAV Plugin (confluence.extra.webdav, Version: 1.1)
Confluence Remote API (confluence.extra.confluencerpc, Version: 1.4)
Profile Tabs (confluence.sections.profile, Version: 1.0)
Admin Sections (confluence.sections.admin, Version: 1.0)
Core Startup and Shutdown (confluence.lifecycle.core, Version: 1)
Sun.com Theme (com.sun.dse.wikis.themes.sundotcom, Version: 1.0.4)
Tabular Metadata (confluence.extra.masterdetail, Version: 1.0)
Table of Contents Plugin (org.randombits.confluence.toc, Version: 2.3.2)
Space Admin Sections (confluence.sections.space.admin, Version: 1.0)
TinyMCE Editor Plugin (com.atlassian.confluence.extra.tinymceplugin, Version: 1.12)
Space Pages Sections (confluence.sections.space.pages, Version: 1.0)
Atlassian Plugin Repository (confluence.repository.client, Version: 2.0.4)
IM Presence NG Plugin (confluence.extra.impresence2, Version: 2.0-rc2)
Advanced Macros (confluence.macros.advanced, Version: 1.3)
Space Advanced Sections (confluence.sections.space.advanced, Version: 1.0)
News Tabs (confluence.sections.news, Version: 1.0)
IM Presence Macros (confluence.extra.impresence, Version: 0.1)
Attachments Macros (confluence.extra.attachments, Version: 1.4)
Confluence Contributors Plugin (com.atlassian.confluence.contributors, Version: 1.1)
Edit Profile Sections (confluence.sections.profile.edit, Version: 1.0)
Space Actions Sections (confluence.sections.space.actions, Version: 1.0)
Task List Macros (confluence.extra.tasklist, Version: 1.3)
Space Labels Sections (confluence.sections.space.labels, Version: 1.0)
Attachment Extractors (confluence.extractors.attachments, Version: 1.4)
Dynamic Task List Macros (confluence.extra.dynamictasklist, Version: 1.5)
Core Extractors (confluence.extractors.core, Version: 1.4)
BloggingRPC (com.atlassian.confluence.plugins.xmlrpc.bloggingrpc, Version: 1.2.1)
Compatibility Macros (confluence.macros.compatibility, Version: 1.3)
Code Macro (confluence.macros.code, Version: 1.4)
Space Item Tabs (confluence.sections.space, Version: 1.0)

Request
Information:
URL: http://wikis.sun.com/500page.jsp

• Scheme: http
• Server: wikis.sun.com
• Port: 80
• URI: /500page.jsp
• - Context Path:
• - Servlet Path: /500page.jsp
• - Path Info: null
• - Query String: searchType=searchByMembership&membersOfGroupTerm=igorminar&onPopupSubmit=addViewPermissionsUsers

Attributes:

• javax.servlet.forward.request_uri : /users/userpicker.action
• javax.servlet.forward.context_path :
• javax.servlet.forward.servlet_path : /users/userpicker.action
• javax.servlet.forward.path_info : /500page.jsp
• javax.servlet.forward.query_string : searchType=searchByMembership&membersOfGroupTerm=igorminar&onPopupSubmit=addViewPermissionsUsers
• javax.servlet.error.message :
• javax.servlet.error.exception : java.lang.NullPointerException
• os_securityfilter_already_filtered : true
• _sitemesh_using_stream : false
• com.atlassian.johnson.filters.JohnsonFilter_already_filtered : true
• javax.servlet.error.request_uri : /users/userpicker.action
• javax.servlet.error.status_code : 500
• _sitemesh_filterapplied : true
• javax.servlet.error.servlet_name : action
• webwork.valueStack : com.opensymphony.xwork.util.OgnlValueStack@cf3e24
• atlassian.core.seraph.original.url : /users/userpicker.action?searchType=searchByMembership&membersOfGroupTerm=igorminar&onPopupSubmit=addViewPermissionsUsers
• loginfilter.already.filtered : true
• javax.servlet.jsp.jspException : java.lang.NullPointerException
• sessioninview.FILTERED : true
• com.atlassian.core.filters.gzip.GzipFilter_already_filtered : true

Parameters:

• searchType = searchByMembership
• onPopupSubmit = addViewPermissionsUsers
• membersOfGroupTerm = admin
  Confluence User:
• anonymous

Logging:
0 log statements generated by this request.