Authenticating in one Domain and querying users from another in Java

Question

Is it possible to authenticate users in Active Directory Server A, and then search for users in Active Directory Server B using java? These servers are configured to be 2-way trusted.

The above code fails. I can authenticate in server A perfectly fine, but when I start searching for users in B, it returns nothing

    Hashtable<String, String> env = new Hashtable<String, String>();
    env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    env.put(Context.PROVIDER_URL, "ldap://A.AD.COM:389");
    env.put(Context.SECURITY_AUTHENTICATION, "simple");

    StringBuffer principal = new StringBuffer("user@A");
    env.put(Context.SECURITY_PRINCIPAL, principal.toString());
    env.put(Context.SECURITY_CREDENTIALS, "password");

    env.put(Context.REFERRAL, "follow");
    InitialLdapContext ctx = new InitialLdapContext(env, null);

    String base = "DC=b,DC=ad,DC=com";

    String filter = "(&(objectClass=user))";

    SearchControls controls = new SearchControls();
    String []strReturningAttr = null;
    controls.setSearchScope(SearchControls.SUBTREE_SCOPE);

    NamingEnumeration answer = ctx.search(base, filter, controls);