Accessing inner class from method

[Salim Mohamed]

Can anyone explain me how can I create an instance of the class Inner ?
class ClassInsideMethod{
public void aMethod(){
class Inner{
public Inner(){
System.out.println("Inner class constructor invoked");
}
}//end of inner class
}//end of method
public static void main (String args []){
ClassInsideMethod m = new ClassInsideMethod();
}//end of main
}//end of class
What is the default access specifier for constructor ?
Thanks in advance.

[Kelvin Mak]

Hi Salim, the Inner class define inside method, so just add the instance stmt at the inner class.

 
class ClassInsideMethod{
    public void aMethod(){
        class Inner{
            public Inner(){
                System.out.println("Inner class constructor invoked");
            }
        }
        Inner i = new Inner(); // instace the Inner class.
    }
    public static void main (String args []){
        ClassInsideMethod m = new ClassInsideMethod();
        m.aMethod() ;
    }
}

[Salim Mohamed]

Thanks Kevin. What if the inner class is defined static (i.e. nested). How can I inovke ?

[Kelvin Mak]

In your example, the Inner class define inside method is private to the method and cannot be marked with any access modifier, neither can they be marked as static. It will get a compiler error. If the Inner class outside the method, you can invoke like this.

class ClassInsideMethod{
    public void aMethod(){}
    static class Inner{
        public Inner(){
            System.out.println("Inner class constructor invoked");
        }
    }
    public static void main (String args []){
        Inner i = new ClassInsideMethod.Inner();
    }
}  

A static inner class does not have any reference to an enclosing instance. Because of this, methods of a static inner class cannot use the keyword this(either implied or explicit) to access instance variables of the enclosing class. Thsi is just the same as the rules that apply to static methods in ordinary classes. You can create an instance of static inner class without the need for a current instance of the enclosing class.
That is all