Nested Interface

[Joe Harry]

Hi all,

I have a doubt regarding inner classes and interfaces. Can anyone please clarify this to me. Consider the below code and tell me why it gives error in the lines commented,

public void TopLevelClass{
 public void method1(){System.out.println("In top level class");}
 
private static class StaticMemberClass_1{
 private static int 1;
 private int j;
 
public static void method2(){System.out.println("In StaticMemberClass_1");}
 
interface StaticMemberInterface_1{int kk = 2000;}
 
protected static class StaticMemberClass_1_1 implements StaticMemberInterface_1{
 private int k = kk;
public void nonStaticMethod_1_1_1(){
 int ll = j; //why compile error here?
}
public static void main(String args[]){
int mm = k; //why error here? Is it that k is implicitly static?
}
}
}
}

Thanks in advance.

Regards,
Jothi Shankar Kumar. S

[Rajesh Kadle]

In both cases static reference is made to non-static fileds, hence the compiler error.

Static context relates to class, it works with class. It has no reference like this or super, so we cant access the non-static fields from static context.

Other way, accessing static fields from non-static context is allowed as each instance is related to the class.

[Joe Harry]

Hai,

I just want to know if in the above code, the line,

interface StaticMemberInterface_1{int kk = 2000;}

Is kk implicitly static?

Regards,
Jothi Shankar Kumar. S

[Rajesh Kadle]

yes, all fields inside an interface are implicitly static and final.