[Java] Can Someone Explain Me How .dex files Work ?

Question

I Don't Understand Like They Tell You .dex files Are A Virtual Machine For Android Then They Tell You It's A File How Does It Work
I Didn't Understand The Part With "Bytescode" Can Someone Explain To Me ?

Answer 1

@Ace I Read About Them But I Didn't Understand Those Two Parts:
1-Why Do They Call It A Virtual Machine
2-Didn't Understand What They Mean By Bytescode Like Is It Some Type Of Encoding ?

Answer 2

@Ace Thanks For Answer :)