Implemenet/Extend interface/class in default package

Filename: DeaultInterface.java
public interface DefaultInterface {
// Abstract Methods...
Filename: ConcreteClass.java
package com.company;
import DefaultInterface;
public class ConcreteClass implements DefaultInterface {
// Implementation of Abstract Methods...
}When I compile above java code it gives error "cannot find symbol. symbol: class DefaultInterface".
Can anyone explain why can't we implement the interface/extend the class in default package(no package)?
Edited by: 974531 on Dec 2, 2012 11:07 PM

>
When I compile above java code it gives error "cannot find symbol. symbol: class DefaultInterface".
Can anyone explain why can't we implement the interface/extend the class in default package(no package)?
>
You CAN implement the interface defined in the default package.
What you CANNOT do is import it. And that is because the Java Language Specification specifies that named types can only be referenced by their simple name if they are imported and must otherwise be referenced by their fully qualified name.
See the 7.5 Import Declarations in the Java Language Specification - http://docs.oracle.com/javase/specs/jls/se7/html/jls-7.html
>
An import declaration allows a named type or a static member to be referred to by a simple name (§6.2) that consists of a single identifier.
Without the use of an appropriate import declaration, the only way to refer to a type declared in another package, or a static member of another type, is to use a fully qualified name (§6.7).
A type in an unnamed package (§7.4.2) has no canonical name, so the requirement for a canonical name in every kind of import declaration implies that (a) types in an unnamed package cannot be imported, and (b) static members of types in an unnamed package cannot be imported. As such, §7.5.1, §7.5.2, §7.5.3, and §7.5.4 all require a compile-time error on any attempt to import a type (or static member thereof) in an unnamed package.
>
So you can't reference that type by importing it because you can't import a type that doesn't have a canonical nmae. And you can't just use the simple name because, as the first statement above says you have to import it to use the simple name.
When you use the simple name of that type without an import the simple name would refer to a class IN your 'com.company' named package.

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Message was edited by:
confused_in_java

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matches in the cupboard above the fridge... and get
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Christians don't drink on Sunday. So there's more for
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Message was edited by:
confused_in_java

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Implemenet/Extend interface/class in default package

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