package com.fatico.winthing;

public abstract class Settings {

    public static final String BROKER_URL = "winthing.brokerUrl";
    public static final String BROKER_USERNAME = "winthing.brokerUsername";
    public static final String BROKER_PASSWORD = "winthing.brokerPassword";
    public static final String CLIENT_ID = "winthing.clientId";
    public static final String TOPIC_PREFIX = "winthing.topicPrefix";
    public static final String RECONNECT_INTERVAL = "winthing.reconnectInterval";

}

package com.fatico.winthing;

public abstract class Settings {

    public static final String BROKER_URL = "broker";
    public static final String BROKER_USERNAME = "username";
    public static final String BROKER_PASSWORD = "password";
    public static final String CLIENT_ID = "clientid";
    public static final String TOPIC_PREFIX = "prefix";
    public static final String RECONNECT_INTERVAL = "reconnect";
}

Remove prefix from config variables