wso2 Identity server soap userStoreConfigAdminService - editUserStore throws unknown error - soap

Question

I am trying to update userstore config through wso2 Identity Server soap service (userStoreConfigAdminService - editUserStore).
Response -
<soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
<soapenv:Body>
<soapenv:Fault>
<soapenv:Code>
<soapenv:Value>soapenv:Receiver</soapenv:Value>
</soapenv:Code>
<soapenv:Reason>
<soapenv:Text xml:lang="en-US">unknown</soapenv:Text>
</soapenv:Reason>
<soapenv:Detail/>
</soapenv:Fault>
</soapenv:Body>
</soapenv:Envelope>
I have traced the wso2carbon.log. the log says some null pointer exception.
TID: [0] [IS] [2015-10-21 12:14:14,609] ERROR {org.apache.axis2.rpc.receivers.RPCInOnlyMessageReceiver} - Exception occurred while trying to invoke service method editUserStore {org.apache.axis2.rpc.receivers.RPCInOnlyMessageReceiver}
java.lang.NullPointerException
at java.util.concurrent.ConcurrentHashMap.hash(ConcurrentHashMap.java:333)
at java.util.concurrent.ConcurrentHashMap.remove(ConcurrentHashMap.java:1175)
at org.wso2.carbon.caching.impl.CacheImpl.getAndRemove(CacheImpl.java:486)
at org.wso2.carbon.identity.user.store.configuration.UserStoreConfigAdminService.getAndRemoveRandomPasswordContainer(UserStoreConfigAdminService.java:713)
at org.wso2.carbon.identity.user.store.configuration.UserStoreConfigAdminService.addProperties(UserStoreConfigAdminService.java:382)
at org.wso2.carbon.identity.user.store.configuration.UserStoreConfigAdminService.writeUserMgtXMLFile(UserStoreConfigAdminService.java:607)
at org.wso2.carbon.identity.user.store.configuration.UserStoreConfigAdminService.editUserStore(UserStoreConfigAdminService.java:236)
at sun.reflect.GeneratedMethodAccessor780.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.axis2.rpc.receivers.RPCUtil.invokeServiceClass(RPCUtil.java:212)
at org.apache.axis2.rpc.receivers.RPCInOnlyMessageReceiver.invokeBusinessLogic(RPCInOnlyMessageReceiver.java:66)
at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:110)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
at org.apache.axis2.transport.http.HTTPTransportUtils.processHTTPPostRequest(HTTPTransportUtils.java:172)
at org.apache.axis2.transport.http.AxisServlet.doPost(AxisServlet.java:146)
at org.wso2.carbon.core.transports.CarbonServlet.doPost(CarbonServlet.java:231)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:755)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:487)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
at org.eclipse.equinox.http.servlet.internal.RequestDispatcherAdaptor.forward(RequestDispatcherAdaptor.java:30)
at org.wso2.carbon.redirector.servlet.ui.filters.AllPagesFilter.doFilter(AllPagesFilter.java:156)
at org.eclipse.equinox.http.helper.FilterServletAdaptor.service(FilterServletAdaptor.java:37)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.wso2.carbon.tomcat.ext.filter.CharacterSetFilter.doFilter(CharacterSetFilter.java:61)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:178)
at org.wso2.carbon.tomcat.ext.valves.CarbonTomcatValve$1.invoke(CarbonTomcatValve.java:47)
at org.wso2.carbon.webapp.mgt.TenantLazyLoaderValve.invoke(TenantLazyLoaderValve.java:62)
at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:47)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:141)
at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:156)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:52)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1653)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Could anyone help to resolve this issue.
Thanks