private static nested class

[Tareq Shaheen]

Hi everyone,
I'm practicing nested classes. I've written this simple class:

public class OuterClass {
private static class InnerClass {
private InnerClass() {
System.out.println("in constructor" }
}
}
}
and another simple class to test:
public class TestClass {
public static void main(String[] args) {
OuterClass.InnerClass in= new OuterClass.InnerClass();
}
}
All classes compile and main method runs with no problem. Now I wonder what is the meaning of the private modifier here ??
Thanks

[Zkr Ryz]

Wait a minute , this doesn't compile!!...
You could probably be watching another source code..

  
public class OuterClass {
    private static class InnerClass {
        private InnerClass() {
            System.out.println("in constructor");
        }
    }
}
public class TestClass {
    public static void main(String[] args) {
        OuterClass.InnerClass in= new OuterClass.InnerClass();
    }
}
$ javac TestClass.java
TestClass.java:6: OuterClass.InnerClass has private access in OuterClass
        OuterClass.InnerClass in= new OuterClass.InnerClass();
                  ^
TestClass.java:6: OuterClass.InnerClass has private access in OuterClass
        OuterClass.InnerClass in= new OuterClass.InnerClass();
                                                ^
TestClass.java:6: InnerClass() has private access in OuterClass.InnerClass
        OuterClass.InnerClass in= new OuterClass.InnerClass();
                                  ^
3 errors

??? Strange don't you think ?

Originally posted by Tareq Shaheen:
Hi everyone,
I'm practicing nested classes. I've written this simple class:

public class OuterClass {
private static class InnerClass {
private InnerClass() {
System.out.println("in constructor" }
}
}
}
and another simple class to test:
public class TestClass {
public static void main(String[] args) {
OuterClass.InnerClass in= new OuterClass.InnerClass();
}
}
All classes compile and main method runs with no problem. Now I wonder what is the meaning of the private modifier here ??
Thanks

[Mike Forsberg]

As you may have noticed from the above responce the private keyword in the inner class is the access modifier. Thus, TestClass's methods have no access to InnerClass. Hovever, OuterClass could use and modify the InnerClass.

[Anthony Villanueva]

Now I wonder what is the meaning of the private modifier here ??

If you like, you can imagine your static InnerClass as some sort of "static variable" of OuterClass. The analogy is not so farfetched; given a static variable
static int someStaticVariable;
defined in OuterClass, it only makes sense to access someStaticVariable outside of OuterClass's class scope as OuterClass.someStaticVariable.
Now, this InnerClass can instantiate objects. How accessible are these InnerClass objects to outside classes? These are defined by the access modifiers you set for your inner class declaration. Since you've declared InnerClass as private, outside classes like TestClass has a much of a chance accessing InnerClass objects as accessing OuterClass.someStaticVariable, if you declared
private static int someStaticVariable;
in your OuterClass declaration.
-anthony

[Tareq Shaheen]

Ok, I'm using Oracle's JDeveloper 3.2 ( jdk1.2.2). The code I posted compiles and runs with no errors in Jdeveloper.
However, I tested this on the command line ( using javac directly ) and it does not compile ! .