title: KEYCLOAK: Obtaining Access token by 'user name' only (without password)
body: <p>I have a question regarding Keycloak and obtaining an Access Token.</p>
  
  <p><strong>Our setup is as follows:</strong>
  ·         users are created and maintained in Keycloak
  ·         resources, policies and permissions are also maintained in Keycloak</p>
  
  <p><strong>Our use case is</strong>:</p>
  
  <p>As a third party application, I want to obtain authorization information (e.g. resource- and scope-based permissions) for a specific user by only providing the username to Keycloak, so I can allow or prohibit further actions.</p>
  
  <p><strong>To be more specific</strong>:
  In our application the need to validate each request to other services based on the access token.But we have only the user name with us.</p>
  
  <p><strong>The question is now:</strong></p>
  
  <p><strong>></strong> How can we obtain an access token for the user by only knowing the username ?</p>
  
  <p><strong>></strong>
  Is there a solution to obtain an access token for such a user?</p>