How do a LDAP search/authenticate against this LDAP in Java

I am playing with LDAP and Java search. Here's my LDIF export with a simple organization

version: 1

dn: dc=example,dc=com
objectClass: organization
objectClass: dcObject
objectClass: top
dc: example
o: MyOrganization
description: Test Description

dn: ou=people, dc=example,dc=com
objectClass: organizationalUnit
objectClass: top
ou: people
description: All users in demo company

dn: cn=Johnny Doe,ou=people,dc=example,dc=com
objectClass: organizationalPerson
objectClass: person
objectClass: inetOrgPerson
objectClass: top
cn: Johnny Doe
sn: Johnny
homephone: 123-456-7890
mail: johnny@johnny.com
ou: Development
uid: jjohnny
userpassword:: johnny

dn: cn=Samuel Johnson,ou=people,dc=example,dc=com
objectClass: organizationalPerson
objectClass: person
objectClass: inetOrgPerson
objectClass: top
cn: Samuel Johnson
sn: Samuel
homephone: 123-456-7890
mail: sam@ssam.com
ou: Accounts
uid: ssam
userpassword:: sammy

How do I run a Java snippet to get all users from the LDAP server? There's no authentication set-up on my Apache DS Directory Server.

Hashtable env = new Hashtable(11);
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldap://localhost:10389/dc=example,dc=com");
env.put(Context.SECURITY_AUTHENTICATION, "none");

try {
    // Create initial context
    DirContext ctx = new InitialDirContext(env);
    Object obj = new Object();
    // want to print all users from the LDAP server
    System.out.println(obj.toString());
    ctx.close();
}

try {
    LdapContext ctx = new InitialLdapContext(env, null);
    ctx.setRequestControls(null);
    NamingEnumeration<?> namingEnum = ctx.search("ou=people,dc=example,dc=com", "(objectclass=user)", getSimpleSearchControls());
    while (namingEnum.hasMore ()) {
        SearchResult result = (SearchResult) namingEnum.next ();    
        Attributes attrs = result.getAttributes ();
        System.out.println(attrs.get("cn"));

    } 
    namingEnum.close();
} catch (Exception e) {
    e.printStackTrace();
}

private SearchControls getSimpleSearchControls() {
    SearchControls searchControls = new SearchControls();
    searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
    searchControls.setTimeLimit(30000);
    //String[] attrIDs = {"objectGUID"};
    //searchControls.setReturningAttributes(attrIDs);
    return searchControls;
}