Hie Paul,
I understand that option two on this question is correct since the compare can use the compareTo method to return a result, however i cannot explain what is wrong with option three:
Collections.sort(al, new Comparable<Person>(){ public int compare(Person o1, Person o2) { return o1.dob.compare(o2.dob); } });
May u please explain to me why option three is not correct
About Question enthuware.ocpjp.v7.2.1725 :
Moderator: admin
-
- Posts: 6
- Joined: Thu Dec 31, 2015 1:40 am
- Contact:
-
- Site Admin
- Posts: 10065
- Joined: Fri Sep 10, 2010 9:26 pm
- Contact:
Re: About Question enthuware.ocpjp.v7.2.1725 :
Well, as the explanation notes, you need to pass a Comparator as the second argument to the Collections.sort method. While option 3 is passing a Comparable. So it won't compile.
HTH,
Paul.
HTH,
Paul.
If you like our products and services, please help us by posting your review here.
-
- Posts: 6
- Joined: Thu Dec 31, 2015 1:40 am
- Contact:
Re: About Question enthuware.ocpjp.v7.2.1725 :
Sorry i meant option four wich is passing a Comparator:
Collections.sort(al, new Comparator<Person>(){
public int compare(Person o1, Person o2) {
return o1.dob.compare(o2.dob); } });
I dont seem to get what is wrong with it, may you please explain
Collections.sort(al, new Comparator<Person>(){
public int compare(Person o1, Person o2) {
return o1.dob.compare(o2.dob); } });
I dont seem to get what is wrong with it, may you please explain
-
- Site Admin
- Posts: 10065
- Joined: Fri Sep 10, 2010 9:26 pm
- Contact:
Re: About Question enthuware.ocpjp.v7.2.1725 :
dob is a String and String doesn't have compare method so the line return o1.dob.compare(o2.dob); will not compile.
You may want to try compiling the code.
HTH,
Paul.
You may want to try compiling the code.
HTH,
Paul.
If you like our products and services, please help us by posting your review here.
-
- Posts: 6
- Joined: Thu Dec 31, 2015 1:40 am
- Contact:
Re: About Question enthuware.ocpjp.v7.2.1725 :
Thank you Paul, I got it now!
Who is online
Users browsing this forum: No registered users and 103 guests