What is the use of Virtualization or Containers and why is that important in Software Development?

Question

So I have a weird question actually, I keep hearing about virtualization and containers(Linux) and software like Docker and that those are important in app Development but I can't see the point here, why is it important? I mean why should I use Virtualization and use some other Os to test or develop my app? Can't I develop an app on windows and then it ll run perfectly fine on ios or Linux?? I thought that's what Java for, when they built the language the purpose was that the code will be written once and it ll work on windows, ios or Linux etc... So why I keep hearing and seeing virtualization everywhere and that it is important in the field of app programming. Now I must say I m a beginner and I haven't build an app yet and see what problem ll I become, but this question is a pain for me and when I read on internet about this thing I didnt found a good answer. In fact I don't understand the answers of other people, so if anyone help me I ll be thankfull.

Answer 1

I guess your issue is about INTEROPERABILITY. Reading on Computer Architecture concepts may help you understand the concern better.

Answer 2

You cannot get around this due to a variety of reasons such as intellectual property rights, etc. Linux is portable across different platforms.

But we can develope applications that can share information across platforms. This is what INTEROPERABILITY is all about.

Answer 3

So the challenge is making applications that communicate across platforms (payroll & hr, etc) and the architure already has provisions for this

https://searchnetworking.techtarget.com/definition/OSI