code: public DirContext createDirContext() throws NamingException {
          LOGGER.debug("Creating directory service context (DirContext)");
          final Hashtable<String, String> env = new Hashtable<>();
          env.put(Context.SECURITY_PRINCIPAL, BIND_USERNAME);
          env.put(Context.SECURITY_CREDENTIALS, BIND_PASSWORD);
          env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
          env.put(Context.PROVIDER_URL, LDAP_URL);
          if (IS_LDAP_SSLTLS) {
              env.put("java.naming.ldap.factory.socket", "alpine.crypto.RelaxedSSLSocketFactory");
          }
          return new InitialDirContext(env);
      }
docs: Creates a DirContext with the applications configuration settings.
  @return a DirContext
  @throws NamingException if an exception is thrown
  @since 1.4.0