Protected Visibility - what am I missing?

[Jaspreet Singh]

 
 
package com.test.parent;
 
class MyObject {
 
protected void protectedmethod() {
 
}
}
 
package com.test.children;
 
class MySubclass extends MyObject {
 
void somemethod() {
protectedmethod(); // Available from MyObject
}
// Has an implicit protectedMethod() inherited from MyObject.
}
 
class Test {
 
void somemethod() {
MySubclass sub = new MySubclass();
sub.protectedmethod(); // Not Visible Error.
// Isnt protectedmethod() available in sub via inheritence??
 
}
}
 

Why is CODE] sub.protectedmethod()[ [/CODE]giving a visibiliy error.

Why should it matter to visibility where from (Test) I am invoking the object's method, all that should matter is what is available to the object that I am invoking the method on. And of course, the protectedmethod() is available to MySubClass via inheritence from MyObject.

[Layne Lund]

Originally posted by Jaspreet Singh:
[CODE]
Why should it matter to visibility where from (Test) I am invoking the object's method, all that should matter is what is available to the object that I am invoking the method on. And of course, the protectedmethod() is available to MySubClass via inheritence from MyObject.

True, protectedmethod() is available to MySubClass, but it is NOT available to Test because it's protected. The visibility modifiers (public, protected, and private) affect what other classes are allowed to call a method. Since protectedmethod() is protected, it can only be called by subclasses (and technically by other non-subclasses in the same package as well). Since Test is not a subclass and in a different package, it cannot call protectedmethod(). In order to allow Test to call the method, you need to redeclare it as public in MySubclass.

Layne

[Jaspreet Singh]

The visibility modifiers (public, protected, and private) affect what other classes are allowed to call a method.

Well, if thats true, then making Test a subclass of MyObject should allow sub.protectedmethod(), isnt it? It still gives an error.

 
class MySubclass extends MyObject {
 
void somemethod() {
protectedmethod(); // Available from MyObject
}
// Has an implicit protectedMethod() inherited from MyObject.
}
 
class Test extends MyObject{
 
void somemethod() {
MySubclass sub = new MySubclass();
sub.protectedmethod();
 
}
}