JIRA fails with "java.lang.OutOfMemoryError: Java heap space" coming from i18nBean

Steps:
1. JIRA is installed on VMware image having winXp.
2. Anonymous access for browse project is there.
3. I was working on auto complete as anonymous user.
4. Executed query related to project and issue type and subtask.

Result:
1. After around 45 mins of working, browser suddenly become slow and inaccessible.
2. Later there was memory eror in tomcat window.
3. Last query execute was issue type and Auto complete for it suddenly stop working.
4. Log file attached.

Expected :
1. No memory error should happen. Any error should be handled gracefully.