JAVA内存使用扩展类

Question

The situation: I have parent class PARENT. Several classes which extends PATENT.

So question is: in memory is created as much copies of PARENT as there is CHILDS. Or in memory there is only one copy which is used by all CHILDS?

Answer 1

每个CHILD方法，每个PARENT方法等只有一个副本。每个CHILD对象都有其类的每个非静态字段，每个PARENT的非静态字段以及每个Object的非静态字段的副本。静态字段。

Answer 2

Instance of a class consists of its parents fields and its own fields.

class A {
   int a;
}

class B extends A {
    int b;
}

instance of B is one instance (no A instance is created) which has 2 fields: int a and int b