@JsonIgnore
    public boolean isExpired() {

        // Do not bother comparing if this UserData object does not expire
        Long expirationTimestamp = getExpires();
        if (expirationTimestamp == null)
            return false;

        // Otherwise, compare expiration timestamp against system time
        return System.currentTimeMillis() > expirationTimestamp;

    }
Returns whether the data within this UserData object is expired, and
thus must not be used, according to the timestamp returned by
getExpires().

@return
    true if the data within this UserData object is expired and must not
    be used, false otherwise.
extensions/guacamole-auth-json/src/main/java/org/apache/guacamole/auth/json/user/UserData.java