Why does this Java code compile?

Question

In method or class scope, the line below compiles (with warning):

int x = x = 1;

In class scope, where variables get their default valu

Answer 1

Let's break it down step by step, right associative

int x = x = 1

x = 1, assign 1 to a variable x

int x = x, assign what x is to itself, as an int. Since x was previously assigned as 1, it retains 1, albeit in a redundant fashion.

That compiles fine.

int x = x + 1

x + 1, add one to a variable x. However, x being undefined this will cause a compile error.

int x = x + 1, thus this line compile errors as the right portion of the equals will not compile adding one to an unassigned variable