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Java Introducing Lambdas

Posted by Lawrence Babay
Lawrence Babay
6,941 Points

Error

I'm not sure why I keep getting an error in usingLamdasInLongForm, I tried carefully checking what I'm missing but at this point I just can't find the flaw. please help. Thanks!

import java.util.Collections; import java.util.Comparator; import java.util.List;

public class Main {

public static void usingAnonymouslineClass () {
    List<Book> books = Books.all();
    Collections.sort(books, new Comparator<Book>() {
        @Override
        public int compare(Book b1, Book b2) {
            return b1.getTitle().compareTo(b2.getTitle());
        }
    });

    for (Book book : books) {
        System.out.println(book);
    }
}

public static void usingLamdasInLongForm() {
    List<Book> books = Books.all();
    Collections.sort(books, (Book b1, Book b2) -> {
        return b1.getTitle().compareTo(b2.getTitle());

    });

    for (Book book : books) {
        System.out.println(book);
    }
}


public static void main(String[] args) {
// write your code here
    usingLambdasInLongForm();

}

}

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

Telling us what the error you're getting and at what line would be a big help in figuring out the issue.

Lawrence Babay
Lawrence Babay
6,941 Points

Hi Seth,

the error I'm getting "Overrides method in java.util.Comparator" at line 25.

public static void usingLambdasInLongForm() { List<Book> books = Books.all(); Collections.sort(books, (Book b1, Book b2) -> { return b1.getTitle().compareTo(b2.getTitle()); });

Thanks