DefaultMethodsExample.java

/**
     * SmartRadio enough smart which let you tune your 
     * favorite channel in louder and lower volumes
     * Now added smartness of auto tuning channel
     */
    public interface SmartRadio {

        //old declared methods
        public void tuneChannel(float channelFrequency);

        //old declared methods
        public void increaseVolume();

        //old declared methods
        public void decreaseVolume();

        //new method added
        default public void autoTuneChannel() {
            System.out.println("auto tune channel feature added");

        }
    }

    /**
     * ABC company has now launched their next smart {@link ABCAutoTuneRadio} 
     * which is type of SmartRadio but with added auto tune feature.
     */
    public class ABCAutoTuneRadio extends ABCRadio {

        final float MIN_FREQ = 85.00F;
        final float MAX_FREQ = 110.00F;

        @Override
        public void autoTuneChannel() {
            for (float startFreq = MIN_FREQ; startFreq <= MAX_FREQ; startFreq += 1.0) {
                tuneChannel(startFreq);
                if (channel.isTuned()) {
                    break;
                }
            }
            System.out.println("channel auto tuned to : " + getFrequency());
        }
    }