Kotlin Singleton Tutorial - Companion Object, Operator Invoke

In this Kotlin Singleton Tutorial, we will learn how easy it is to use Singleton Pattern in Kotlin. (Compared to other languages such as Java).

Singleton is an Object Oriented Design Pattern, and it is used when we want to have only a single instance of a class, that is shared throughout the application. It is often require, when the instance is frequently needed, so instead of creating the instance again and again, we can restrict it to just a single instance that will be shared throughout the application.

Kotlin makes, singleton very easy with zero boilerplate code. We just need to use the keyword object and the Singleton class is ready. Let's find out the whole step in this video.

0:00 What is Singleton?
0:42 Singleton the Old School Way
1:47 Companion Object
4:41 Invoke Operator
5:30 Problem with the Approach
5:54 Singleton, The Kotlin Way


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[deeprajpandey]

Sir, you way of teaching is really superb.... keep making videos sir we really like your contents...

[gulfappdeveloper]

Thanks, it is usefull for retrofit & room database in android

[peshutanpavri]

I have learnt a lot from this playlist and I have subscribed, but I have to admit, I dont prefer Kotlin to Java anymore (at this time), maybe I will grow to like it :)

[akashviet]

I don't understand the invoke operator, is it used with only companion block? or it has other uses also?

[mohamedfiyaz]

What's the difference between creating object by singleton method and creating object by lazy delegates?

[veedfriendforever]

good morning,
Hello sir, I am working a project that require some permission that dose not provide normally so, want to know about device policy manager in describe details so please help if you?
thank you

[youmeandeveryone]

Who else liking Kotlin more than Java?😀

[RWSful]

Only the initialization of an object declaration is thread-safe. If you are using this object outside it won't be thread-safe.

[hanki]

Hi Belal, really insightful tutorial about Singleton. I would like to know how can we use the volatile keyword for our instance? Can we do that similar to java by adding volatile keyword ahead of the instance declaration?

[muskanyousaf]

Thnku For the Series 🤝 please make a Video on sockets with Api responses dealing please please🙏

[indra.ndra]

Hi sir.. How to pass a parameter? in case we need the parameter to be passed to object class

[gibraanjafar]

The content is so good, concise and to the point that I don't mind watching the adds. Thanks Belal for this really nice playlist

[tortoiseshell_cat]

Can i user 'instance get()=...' instead of function and wich on is better