Interface and interface methods

[Vikash Agarwal]

If we do not provide access modifier, interface takes 'default' access and interface methods 'public' access?

Why the difference? What sense does it make to have interface methods public when interface itself cannot be seen by other packages? Shouldn't both have been either public or default?

[Prafulla N. Patil]

Interface can be implemented by a which is outside that package means implementing class must have access to methods in interface
and u can specify interface with package extension in implements clause 
which is not possible in case of methods.

[raj malhotra]

Hi prafulla didnt get your answer. can you elaborate it?

[santosh thiruvanagiri]

There can be situation where an Interface needs to be implemented by a class which is in different package as that of interface. But here the implementing class should have access to methods inside the interface.So we give public access specifier for class inside interface by default .
and
In implements clause , U can specify interface name with complete package extension (, which is not possible in case of methods) .
Ex:
class ABC implements com.ex.InterfaceEx

Thank You ,
Santosh Kumar.T

[Chandra Bhatt]

Hi,

It is a contract of an interface that its methods are abstract and public
to be implemented by any class from any class hierarchy or extended by any
interface.

Sometimes you may require that a interface must only be accessed in its
package only, not outside that. But in this case too, you can't violate the
general contract of an interface of being abstract and public.

Suppose there is one interface that is public and that extends the interface
that has default accessibility. Now a new interface you have created
extending the existing one. This interface will be accessible from anywhere
, no package only bound. If the previous interface method were having
default accessibility as you guessed , now you can guess what would
go wrong. Yes, violation of interface contract methods to be accessed.
Any non-abstract class that implements the new interface must implement all
the methods of both the interfaces. So all the methods must be public
accessible.

It is the reason why methods of interface are public and abstract always irrespective of the accessibility of the interface itself.



Thanks,
[ June 22, 2007: Message edited by: Chandra Bhatt ]