Hi
On Apr 16, 8:38 am, Ryu <[email protected]> wrote:
> Hi to all,
> Hope everyone is fine .Sorry i know this matter discussed
> lot of times in previous emails and i m reading all the emails and
> apply the techniques that had been discussed in those emails but since
> last week i am jammed at this homework .
>
> I read that create AddressImpl object in Person class I am
> trying this in different ways .First I did that Person class only
> implements MyOwn Interface and do something like this . I don't
> implements other interfaces because i think its only a matter of
> implements those interfaces methods and that is not difficult because
> they all have int and String type
>
> public class Person implements MyOwnInterface {
>
> AddressInterface address ;
>
> //Constructor
> public Person(AddressInterface address){
> this.address = address;
>
> public AddressInterface getAddress(){
> return address;
> }
>
> And in mian i tried
>
> Person person1 = new Person(new AddressImpl()); //You assign
> object that implements interface
>
> But this gives an error that
> can not find symbol
> symbol: constructor AddressImpl()
>
I do not see the AdressImpl class, but this error does not find
a constructor without any argument.
> Then i replace addressImpl with AddressInterface
>
> Person person1 = new Person( new AddressInterface());
>
> But then it says
> AddressInterface is abstract ; can not be instantiated
>
The error says all -> only classes can be instantiated.
classes can be assigned to variables defined with the interface.
> Then in Person class i try this
>
> public Person(){
> address = new AddressImpl();
> }
>
> and second time replace it with AddressInterface but i again get the
> above mentioned errors
>
> Then i extend the AddressImpl class
>
> public class Person extends AddressImpl implements MyOwnInterface
> {
>
> AddressInterface address ;
>
> public Person(int streetNumber, String streetName, String
> country, AddressInterface address){
> super(streetNumber, streetName, country);
> this.address = address;
> }
>
> public AddressInterface getAddress(){
> return address;
> }
>
> }
>
> But in main what i passed as a 4th parameter when i try to pass an
> instance of class(addressImpl) and interface (AddressInterface) it
> again prompt for an error .
>
The 4th parameter must be an instance of a class which is
implementing
AddressInterface.
> i also try to create an instance in a single line in Person class
> like
> AddressInterface address = new AddressIntercae(); and also try
> AddressImpl address = new AddressImpl();
> but the result is same ERRRRRRRRRooRRRs
Here again. Interfaces can not be instanciated.
>
> can some body help me why all this happen , where i m wrong , what
> mistake i m doing that i didn't figure out
I think, that your problem is the missing constructor without any
arguments in
AddressImpl. Check the the source of AddressImpl.java or supply the
necessary
arguments you defined, when constructing a new instance of
AddressImpl.
HTH
Ewald
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/javaprogrammingwithpassion?hl=en
-~----------~----~----~----~------~----~------~--~---
