Why can't we play android games on ios or Windows without third party software

Question

If a game is written in Java or whatever then it can theoretically be read by any operating system or device if the language is recognizable by the system, right?
I don't know how stupid my question sounds like to experts but it has been bugging me for a long time so indulge me please.
Thanks!

Answer 1

perhaps you came into this conclusion out of the "write once, run anywhere" motto of java.

in theory, java needs a jvm for each different OS so that it can turn java code into their respective OS machine language. that's why java can run on multiple platform thx to the jvm.

currently there are no serious projects to make a jvm for ios. and if it does, not many people would develop ios apps with java. since making ios apps with swift or objective-c is better.

the only option that many people do to make cross-platform games that work on android, ios, windows, mac and web is to use unity with C# where the build can work perfectly on all platforms.

Answer 2

I am not sure about it:
Languages are not meant to be recognize by systems. Every code must change (by compiler or interpreter) to something readable for machines and Operation Systems. I think these compilers make the differences.

If I'm wrong someone plz correct me.
TnX