presto-plugin-toolkit/src/main/java/io/prestosql/plugin/base/authentication/KerberosAuthentication.java/KerberosAuthentication/getSubject
class KerberosAuthentication:    public Subject getSubject()
    {
        Subject subject = new Subject(false, ImmutableSet.of(principal), emptySet(), emptySet());
        try {
            LoginContext loginContext = new LoginContext("", subject, null, configuration);
            loginContext.login();
            return loginContext.getSubject();
        }
        catch (LoginException e) {
            throw new RuntimeException(e);
        }
    }