LDAP connection timeout exception - some times

Question

Hi Team,
I'm using Ldap authentication for my web applications. Everything is working fine most of the times.
But ones in every 15 days or 10 days, I'm getting the connection timeout. But if I restart the tomcat then everything working fine. I couldn't find any
issues with my code. Can anyone please help me on this. below is my java code. I'm keeping all the ldap entries in tomcat's server.xml and getting them in my java code to avoid the hard
code configurations in my java code.
I'm closing the context and naming enumerations like below, but still getting javax.naming.CommunicationException: error.
Can anyone please help me out on this.
public boolean authenticateFromLdap(String username, String password)throws AuthenticationException,Exception {
    LdapContext ctx = null;
    Context newctx = new InitialContext();
    Context envCtx = (Context) newctx.lookup("java:comp/env");
    DirContext ctxDir = (DirContext)envCtx.lookup("ldap/myapp");
    NamingEnumeration<?> namingEnum = null;
    String userDN=null;
    boolean isauthenticated = false;
    try {
        Hashtable env = null;
        Control[] connCtls = null;
        env = ctxDir.getEnvironment();
        env.put(Context.REFERRAL, "follow");
        this.filter = (String)env.get("ldap.filter");
        this.base = (String)env.get("ldap.base");
        try {
            ctx = new InitialLdapContext(env, connCtls);
            ctx.setRequestControls(null);
        } catch (javax.naming.AuthenticationException ex) {
            throw new Exception("ldap.server.exception");
        } catch (Exception ex) {
            throw new Exception("ldap.server.exception");
        try {
            SearchControls searchControls = new SearchControls();
            searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
            searchControls.setTimeLimit(30000);
            String filter="("+this.filter+"="+username+")";
            ctx.setRequestControls(null);
            namingEnum = ctx.search(this.base, filter, searchControls);
            SearchResult result = (SearchResult) namingEnum.next();
            Attributes attrs = result.getAttributes();
            Attribute str1=attrs.get("userprincipalname");
            userDN=str1.get().toString();
            if(userDN==null){
                userDN=username;
            ctx.addToEnvironment(Context.SECURITY_PRINCIPAL,userDN);
            ctx.addToEnvironment(Context.SECURITY_CREDENTIALS,password);
            ctx.reconnect(connCtls);
            isauthenticated = true;
        }catch (AuthenticationException ex) {
            throw new AuthenticationException();
        }catch (NamingException ex) {
            throw new Exception("ldap.server.exception");
        return isauthenticated;
    } finally {
        if (null != namingEnum) {
            try {
                namingEnum.close();
            } catch (Exception e) {
                throw new Exception("close.ldap.failure");
        if (null != ctx) {
            try {
                ctx.close();
            } catch (Exception e) {
                throw new Exception("close.ldap.failure");
}Tomcat (v6.0.14) server.xml:
                <Resource name="ldap/myapp"
                                                auth="Container"
                                                type="com.sun.jndi.ldap.LdapCtx"
                                                factory="com.myapp.MyLdapFactory"
                                                java.naming.factory.initial="com.sun.jndi.ldap.LdapCtxFactory"
                                                com.sun.jndi.ldap.connect.pool="false"
                                                java.naming.provider.url="ldap://ldap.com.test.net:389"
                                                java.naming.security.authentication="simple"
                                                java.naming.security.principal="MyAdmin"
                                                java.naming.security.credentials="xxxxxxx"
                                                ldap.base="DC=com,DC=test,DC=net"
                                                ldap.filter="sAMAccountName"
                />Below is the error log trace:
2013-Mar-26 12:01:34,714 AppUserDetailsService - javax.naming.CommunicationException: ldap.com.test.net:389 [Root exception is java.net.ConnectException: Connection timed out: connect]Note: Once we restart the tomcat, everything is working as usual and after 2 weeks again same problem occuring.
Ganesh
Edited by: EJP on 27/03/2013 14:26: added {noformat}{noformat} tags. Please use them. Your code is unreadable without them.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

1. 'filter' and 'base' need to be local variables, not instance variables, otherwise the method isn't thread-safe.
2. It isn't clear that you are closing the search results or contexts if you get an exception, in all that spaghetti, especially the part where you just catch and rethrow exceptions, which is pointless. You need to rewrite that lot like this:
public boolean authenticateFromLdap(String username, String password) throws AuthenticationException, NamingException
     Context newctx = new InitialContext();
     try
          Context envCtx = (Context)newctx.lookup("java:comp/env");
          try
               DirContext ctxDir = (DirContext)envCtx.lookup("ldap/myapp");
               try
                    String userDN = null;
                    boolean isauthenticated = false;
                    Control[] connCtls = null;
                    Hashtable env = ctxDir.getEnvironment();
                    env.put(Context.REFERRAL, "follow");
                    String     filter = (String)env.get("ldap.filter");
                    String     base = (String)env.get("ldap.base");
                    LdapContext ctx = new InitialLdapContext(env, connCtls);
                    try
                         ctx.setRequestControls(null);
                         SearchControls searchControls = new SearchControls();
                         searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
                         searchControls.setTimeLimit(30000);
                         filter = "(" + filter + "=" + username + ")";
                         ctx.setRequestControls(null);
                         NamingEnumeration<SearchResult> namingEnum = ctx.search(base, filter, searchControls);
                         try
                              SearchResult result = namingEnum.next();
                              Attributes attrs = result.getAttributes();
                              Attribute str1 = attrs.get("userprincipalname");
                              userDN = str1.get().toString();
                              if (userDN == null)
                                   userDN = username;
                              ctx.addToEnvironment(Context.SECURITY_PRINCIPAL, userDN);
                              ctx.addToEnvironment(Context.SECURITY_CREDENTIALS, password);
                              ctx.reconnect(connCtls);
                              isauthenticated = true;
                              return isauthenticated;
                         finally
                              namingEnum.close();
                    finally
                         ctx.close();
               finally
                    ctxDir.close();
          finally
               envCtx.close();
     finally
          newctx.close();
}Also, you are suppressing exceptions when you rethrow. Never do that. Always log the actual exception. But there aren't any exceptions here that need to be caught and rethrown.