Do uninitialized primitive instance variables use memory?

Question

In Java, does it cost memory to declare a class level instance variable without initializing it?
For example: Does int i; use any memory if I don\'t initial

Answer 1

Yes. In your class level variables will assign to its default value even if you don't initialize them.

In this case you int variables will assign to 0 and will occupied 4 bytes per each.