Dependency Injection Explained

This was a great watch. Good job!

Why did MailChimpEmailService Class get annotated with @Service but earlier EmailService Class didn't. Both were injected with ContactListService?

Jazaakallah brother

In general i like that you make a video about this topic. But in detail i am missing some background. You say, it is complicated and a lot code to talk about.
But at least some core mechanics and ideas behind it, would be great to know.
I don't know how spring does its dependency injection, but i know from other framworks they did it more simple and easy.
There you can downsize it to a class register, which registrates all singleton classes and construct these at start.
This register is also able to get additional data from configuration files. Thats the basic idea behind it.
Of course how and what exactly different frameworks do differently can be quite a lot. But i think the idea behind it, is just a mechanism how to ensure, that these classes have always only one instance.
The Service Annotation helps the register to know, that this class needs to be part of the service registry. In some frameworks, you have to put your class in a service config file and do it manually, instead of an annotation.

Great intro, thank you!

You are a great teacher

Question: Does this thing actually make sense only when using Spring and alike frameworks ?

Excellent explanation. Clear and simple. Thanks!

Why is it necessary to tag the method and the field and the dependency class if you are passing the value to the constructor already? Seems like the functions of the tags is to implement the singleton pattern and manage the lifecyle of the instance but the injecting is happening in the constructor, you didn't show how to instantiate the mailChimpEmailService what are we passing to it's construcror?

very insightful, not what I'm looking for in syntax but the explanation is all that I need

Really well explained! Thank you!

Thanks! you explain how and what does this injection is doing so clearly! Subscribed!

Dependency Injection is global variables on steroids

so what is the difference between Injection and Autowire?

My English is bad. Can anyone explain to me why the title is Dependency Injection Explained instead of Explained Dependency Injection? Thank in advance

This explanation is awesome. Thank you!

ma sha Allah! 👍👏

Dependency injection is basically creating an object that, if its a service (aka usually only performs methods with static variables that dont change), then use that same object over and over again rather than creating new ones

Very helpful!

Can you please cover a special video on Junits and Mockito?

Great explanation good job

What if you wouldn't use @Inject? I have already used objects like this without writing @Inject on Spring boot but has worked for me.

Do you recommend learning Guice? Do you Guice tutorials?

amazing

Dependency injection is mostly for changing environments. E.g. Development vs. production. The code will not have to be altered, and the resources will come from different services such as a database and if you are working in dev, you'll get the PostgreSQL service, and if your working in production you'll get the Oracle service.

You explained this really well. Thank you.

Best explanation I heard about the dependency injection. Bravo!

Subtitles come up with “penis’ injection” and I was wondering what I clicked on

Could you make a video about dependency inversion? please 🙏

so your explanation is it's bad for mockito testing, garbage

thank you !

How do we specify the different lifetime scopes for our DI objects .

Genial curso ahora lo entiendo todo

long and similar class names make difficult to chase video. It could have been more simple explanation

I am learning Java now after Javascript. The video is super helpful. Thank you!

Brilliant explanation! Well done

Why did you write @Service for MailChimpEmailService but not for EmailService?

Nelson you’re awesome 👏🏻 you explain everything miraculously. Thanks 🙏🏻

Whats the difference between this and Singleton again

I love you

Which ide and plugins?

Could you make one on Guice?

Very well explained !! Thank you

Thank you indid

Amazing. Thanks.

Best Explanation sir

I speak Spanish, sorry if I have spelling mistakes.
I'm not sure but,I had understood.
i had understand instantiate a class with keyword new , this sentence what you do is use address in memory in memory stack and not heap.

Imagine you want to test your app with fakeapiservicegenerator where you implement an interface contract of 3 function like get user list ,remove an user, and generate a random user (from a fake random user list of let s say 4 e mail) to add that random e mail to the main list like you want to fill it with more user e-mail.
How can I create a new variable (lets say userRandom) and add it to the user list?