Members of static nested class in java

Question

If I define a member variable inside static nested class in java like this:

public class Outer {

    public static class StaticNestedClass {
         private int mMember = 3;
    }

}

mMember would be interpreted static because its class is static? What about static nested class members in java?

Thanks in advance.

score 7 · Accepted Answer · edited May 23 '17 at 12:28

No, static on a class doesn't have the same meaning as staticon a field. The field mMember is a private instance field of the nested class StaticNestedClass. You can use this nested class as if you were using any other top-level class, as long as you import it or use it with reference to its containing class, ie. Outer.StaticNestedClass. For example,

import Outer.StaticNestedClass;

...
StaticNestedClass instance = new StaticNestedClass();

or

import Outer;

...
Outer.StaticNestedClass instance = new Outer.StaticNestedClass();

An inner class cannot declare static members under some rules, see here.

score 1 · Answer 2 · answered May 24 '13 at 17:12

from the java doc

As with class methods and variables, a static nested class is associated with its outer class. And like static class methods, a static nested class cannot refer directly to instance variables or methods defined in its enclosing class — it can use them only through an object reference.

Note: A static nested class interacts with the instance members of its outer class (and other classes) just like any other top-level class. In effect, a static nested class is behaviorally a top-level class that has been nested in another top-level class for packaging convenience. Static nested classes are accessed using the enclosing class name:

OuterClass.StaticNestedClass For example, to create an object for the static nested class, use this syntax:

OuterClass.StaticNestedClass nestedObject =
     new OuterClass.StaticNestedClass();

Members of static nested class in java

2 Answers2