more about nested class topics

[William Yan]

I read Corey's SCJP tiplines on inner class topics, there are 4 types of inner class: inner, nested, anonymous, local. But the terms in Sun Certified Java Programmer Pre-Exam Essentials seem a little different: non-static nested, static nested, amonymous, non-static nested in method's scope. I am not very sure of the terms and concepts that i catch, so i write the code below for REVIEWs if i have made mistakes. Is this enough for the exam? THANK YOU.
Yours,
William.

public class Test {
  public static void main(String[] args) {
    new OuterClass().go();
    new OuterClass().new InnerClass().go();
    new OuterClass.NestedClass().go();
    OuterClass.NestedClass.goStatic();
  }
}
 
class OuterClass {
  int i = 0;
  static int j = 0;
 
  public Object go() {
    final int i = 0;
    class LocalClass { // non-static nested class in method scope?
      void go() {
        System.out.println("local class\t\tuse final local variables:" + i); 
      }
    }
    new LocalClass().go();
    return new Object() { // anonymous class
      {
System.out.println("anonymous class\t\tuse final local variables:" + i); 
      }
    };
  } // end of OuterClass go
 
  // non-static nested class
  class InnerClass {
    void go() {
      System.out.println("inner class\t\tuse non-static instance variables:" + OuterClass.this.i); 
    }
  }
 
  // static nested class
  static class NestedClass {
    void go() {
      System.out.println("nested class\t\tuse static instance variables:" + OuterClass.j); 
    }
    static void goStatic() {
      System.out.println("nested class (static method)");
}
}
}

[ October 17, 2006: Message edited by: William Yan ]

[Maneessh saxena]

Hi William,

Below is the explanation . I hope you will understand clearly after reading this . if you still have any confusion please let me know..


Inner or non-static nested : :

the term Inner here to represent inner classes that are not :

Static
Method-local
Anonymous

Example::

class MyOuter {
private int x = 7;
// inner class definition i.e not static
class MyInner {
public void seeOuter() {
System.out.println("Outer x is " + x);
}
} // close inner class definition
} // close outer class


Nested or static nested ::

Static nested classes referred to as static inner classes, but they really aren't inner classes at all, by the standard definition of an inner class.
While an inner class (regardless of the flavor) enjoys that special relationship with the outer class (or rather the instances of the two classes share a relationship), a static nested class does not.

Actually there is no static class at all.it’s like a static member of a class in which it’s declared.
Example :

class BigOuter {
static class Nested { }
}



Amonymous Class ::


inner classes declared without
any class name at all (hence the word anonymous).

you can define these classes not just within a method, but even within an argument to a method.

Example ::

class Popcorn {
public void pop() {
System.out.println("popcorn");
}
}
class Food {
Popcorn p = new Popcorn() {
public void pop() {
System.out.println("anonymous popcorn");
}
};
}


Laocal or non-static nested in method's scope ::

Any class i.e declared within the scope of a method .even though we can have these classes in loops any block etc.

Example ::

class MyOuter2 {
private String x = "Outer2";
void doStuff() {
class MyInner {
public void seeOuter() {
System.out.println("Outer x is " + x);
} // close inner class method
} // close inner class definition
} // close outer class method doStuff()
} // close outer class



Regards…..

[William Yan]

Thank you, raunak.
The concept seems the same in your code and mine.

Regards,
William