Null in arraylists>object data

Question

I want to know how arraylists work behind the scene in Java?why I get few nulls
https://www.sololearn.com/post/78634/?ref=app

Answer 1

Serena Yvonne but see my post there are 21 elements and 15 are filled so after I cross 10 if new capacity becomes 10*3/2+1 means 16 and I have not crossed it but still 21 elements why?

Answer 2

Serena Yvonne now it's okay since I was also confused why it will be *3/2 +1 and now you have edited it to remove 1 🙂🤔