Observer Design Pattern in Java

Learn: Properties & Implementation with example in Java of Observer Design Pattern

Do Watch video for more info

This Problem is synonym of following problems:
observer design pattern java,
Create notification service,
Kafka topic subscriber service,
real time example for observer design pattern in java,
when to use observer design pattern,
observer design pattern in java,
observer design pattern in spring,
design patterns in java,
observer design pattern implememt,
how kafka topic & observer works

Please check video for more info:

CHECK OUT CODING SIMPLIFIED

★☆★ VIEW THE BLOG POST: ★☆★

I started my YouTube channel, Coding Simplified, during Dec of 2015.
Since then, I've published over 200+ videos.

★☆★ SUBSCRIBE TO ME ON YOUTUBE: ★☆★

★☆★ Send us mail at: ★☆★

[rahuldubey]

watching it now, and its still very good compare to other tutorials. great work @Coding Simplified.

[mohamed_hilowle]

Lucid and very easy to understand. Thank you bro

[shadiismailalzouabi]

You have an easy way to explain, thanks.

[SushilYadav]

Actually as per the GOF, the update method does not take any parameter, instead we get the state(location) from the subject itself by calling subject.getLocation() in the update(). And obviously subject would be as member variable in observer in order to get the state.
Also, when you would pass the subject in the constructor of observer, you would call the subject.register(this) in order to register the observer.
After watching a lot of videos on this pattern, I got to know about it, like how it is written properly.

[dinkarinjosh]

Thank you for the explanation, however I have a doubt. How will we be able to implement if the user wants to know the current location of the "article", if they have not registered? Basically how can they request themselves for the data, instead of being pushed the data? Thanks in advance, nice explanation.

[speedbreaker]

Just want to say one thing Spring framework has ApplicationEventListners which is designed using this pattern. If you can explain how does spring did that things will be too easy....for viewers. Thanks.