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Do Interfaces implicilty subclass Object?

 
Greenhorn
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I read that Interfaces do not belong to the Object Hierarchy..also interfaces do not have any method implementations, but the following code

interface Sample
{
}

class A implements Sample
{
public static void main(String args[])
{
Sample sam = new A();

System.out.println(sam.toString());

}
}

runs well...which means that the interface Sample did has all the methods in the Object class.
So if interfaces do not subclass Object where does toString() come from?
 
Ranch Hand
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From the Java Language Specification:


If an interface has no direct superinterfaces, then the interface implicitly declares a public abstract member method m with signature s, return type re, and throws clause t corresponding to each public instance method m with signature s, return type re, and throws clause t declared in Object, unless a method with the same signature, same return type, and a compatible throws clause is explicitly declared by the interface. It is a compile-time error if the interface explicitly declares such a method m in the case where m is declared to be final in Object.

It follows that is a compile-time error if the interface declares a method with a signature that is override-equivalent (�8.4.2) to a public method of Object, but has a different return type or incompatible throws clause.

 
Ankur Tibrewal
Greenhorn
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thanks a lot that explains it
 
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