Indicator can receive onStop method call when it is removed from platform. To do that indicator needs to implement IStopListener interface and register itself with IndicatorsProvider.

public class Indicator implements IIndicator, IStopListener {

    public void onStart(IIndicatorContext context) {
        ...
        context.getIndicatorsProvider().addIndicatorStopListener(this, this);
    }

    ...

    public void onStop() {
        console.getOut().println("onStop");
    }
}

IndicatorOnStop.java