Implementing WSSubject.getRootLoginException() in Liberty

We are migrating an existing JEE application from WebSphere Traditional to Liberty, and the current application has a custom user registry module. In WebSphere Traditional, we can call WSSubject.getRootLoginException() to get the root cause of login failure. However, in Liberty 24.0.0.x, the method always returns null. By reviewing the source code from com.ibm.websphere.security.auth.WSSubject (even the latest version in Maven - https://mvnrepository.com/artifact/com.ibm.websphere.appserver.api/com.ibm.websphere.appserver.api.basics/1.4.94), it seems the method just returns null without any logic.

public static Throwable getRootLoginException() {
return null;
}

After a conversation with IBM support team (case #TS017587281), IBM support team confirmed the WSSubject.getRootLoginException() functionality was not included in this transition of WebSphere to Liberty.

Since the API is useful and the Java documentation indicates that the function should still be working, it would be beneficial if IBM could implement the API as described in the javadoc in a future release.

    /**
    * <p>
    * This convenient method returns the root login exception caught in the system
    * login module, if one exists.
    * </p>
    * 
    * <p>
    * It will extract the exception from the current thread. You will get what
    * the login module sees as the root exception. This could be a nested exception.
    * You may need to extract exceptions from the exception returned until you
    * get the real root exception.
    * </p>
    * 
    * @return A Throwable containing the root login exception. If a login
    *         exception did not occur, null will be returned.
    */
   public static Throwable getRootLoginException() {
       return null;
   }