commit 21feb1e46d60c45f8f60cf37933ece4d40d4a56d

Author: Devaraj Das <ddas@yahoo-inc.com>
Date:   Sat Mar 20 17:06:36 2010 -0700

    HADOOP:6652 from https://issues.apache.org/jira/secure/attachment/12439372/groups.patch
    
    +++ b/YAHOO-CHANGES.txt
    +    HADOOP-6652. ShellBasedUnixGroupsMapping shouldn't have a cache.
    +    (ddas)
    +


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20-security-patches@1077353 13f79535-47bb-0310-9956-ffa450edef68

src/core/org/apache/hadoop/security/ShellBasedUnixGroupsMapping.java

@@ -35,19 +35,12 @@ import org.apache.hadoop.util.Shell.ExitCodeException;
  * memberships of a given user.
  */
 public class ShellBasedUnixGroupsMapping implements GroupMappingServiceProvider {
-  Map<String, List<String>> userGroups = 
-    new ConcurrentHashMap<String, List<String>>();
   
   private static final Log LOG = LogFactory.getLog(ShellBasedUnixGroupsMapping.class);
   
   @Override
   public List<String> getGroups(String user) throws IOException {
-    List<String> groups = userGroups.get(user);
-    if (groups == null) {
-      groups = getUnixGroups(user);
-      userGroups.put(user, groups);
-    }
-    return groups;
+    return getUnixGroups(user);
   }
 
   /**