title: How authorize in Spring OAuth2 by client_id and secret only?
body: <p>Now I am using the next configuration:  </p>
  
  <pre><code>@Configuration
  @EnableAuthorizationServer
  @EnableGlobalMethodSecurity(prePostEnabled = true)
  public class OAuth2Config extends AuthorizationServerConfigurerAdapter {
  
      @Override
      public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
          clients.jdbc(mAppConfig.dataSource())
                  .withClient("virto")
                  .secret("secret")
                  .authorizedGrantTypes("password", "authorization_code", "refresh_token");
      }
  }
  </code></pre>
  
  <p>It requires to send <code>client_id, client_secret, username, password</code>... But I need to provide <code>access_token</code> for my trusted servers that has <code>client_id</code> and <code>client_secret</code> only... How can I make it? Is it possible?</p>