Inner classes in java

Question

Why can't we declare static members in the non-static inner class in java?

Answer 1

Because an inner class is an instance of the outer class.

https://stackoverflow.com/questions/1953530/why-does-java-prohibit-static-fields-in-inner-classes#:~:text=An%20inner%20class%20is%20a,constant%20fields%20(%C2%A715.28).

Answer 2

we can
if there is static class Inner or
if non-static Inner has static final member

class Outer {
static class Inner{
static int x = 10;
Inner() { System.out.println(x); }
}
public static void main(String args[]) {
new Outer.Inner();
} }

Answer 3

Thank you everyone!