SitePublisher Sitemap not loading

Problem
The Site Publisher Sitemap is not loading in the user interface.
Potential Solution
Reset the user interface services via the iwreset -ui command (e.g) /usr/iw-home/bin/iwreset -ui
Errors seen
(Error in Action)
javax.servlet.ServletException: Java heap space
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:294)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
at com.interwoven.livesite.common.web.action.BaseAction.execute(BaseAction.java:273)
at com.interwoven.livesite.web.LivesiteAction.execute(LivesiteAction.java:78)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.interwoven.livesite.spring.hibernate.web.filter.OpenSessionsInViewFilter.doFilterInternal(OpenSessionsInViewFilter.java:141)