Getting error The method sort(List<T>, Comparator<? super T>) in the type Collections is not applicable for the arguments

Question

I want to sort a collection on basis of enum order, but getting error : The method sort(List, Comparator<? super T>) in the type Collections is not applicable for the arguments

The classes are as following This is the enum class on whos order I need the sorting

package com;

import java.util.Comparator;

public enum MyLink {

    CREATE_LOGIN("My Create login" ,0),
    LISTEN_NOW("My Listen now", 1),
    FREE_PREVIEW ("My FREE PREVIEW", 2);

    private final String value;
    
    private final int order;

    
    
    private MyLink(String value, int order) {
        this.value = value;
        this.order = order;
    }

    public String getValue(){
        return value; 
    }
    
    public int getOrder() {
        return order;
    }

    public static Comparator<MyLink> orderComparator = new Comparator<MyLink>() {
        public int compare(MyLink ctaLink1, MyLink ctaLink2) {
          return ctaLink1.getOrder() - ctaLink2.getOrder();
        }
      };
    
}

This class conatins the MyLink Order.

package com public class Profile {

private MyLink eligibilityType;

private String id;

public MyLink getEligibilityType() {
    return eligibilityType;
}

public void setEligibilityType(MyLink eligibilityType) {
    this.eligibilityType = eligibilityType;
}

public String getId() {
    return id;
}

public void setId(String id) {
    this.id = id;
}

@Override
public String toString() {
    return "Profile [eligibilityType=" + eligibilityType + ", id=" + id + "]";
}

}

Here In TestTrial I am setting the list and calling the collections.sort mwthod which is throwing error Getting error The method sort(List, Comparator<? super T>) in the type Collections is not applicable for the arguments

package com;
    import java.util.List;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.*;
    
    
    public class TestTrial {
    
        public static void main(String[] args) {
            System.out.println("hello");
            List<Profile> prolifes = new ArrayList<Profile>();
            Profile n1 = new Profile();
            n1.setId("2");
            n1.setEligibilityType(MyLink.FREE_PREVIEW);
            
            prolifes.add(n1);
            
            
            Profile n2 = new Profile();
            n2.setId("1");
            n2.setEligibilityType(MyLink.CREATE_LOGIN);     
            prolifes.add(n2);
            
            Profile n3 = new Profile();
            n3.setId("3");
            n3.setEligibilityType(MyLink.LISTEN_NOW);       
            prolifes.add(n3);
            
            for(Profile n : prolifes) {
                System.out.println("n::" + n );
            }
            
            //Collections.sort(nonPiiSubscriptions, CTALink.orderComparator);
            //nonPiiSubscriptions.sort(Comparator.comparing(nonPiiSubscriptions::name));
    
    
            Collections.sort(prolifes, new Comparator<MyLink>()
            {
                @Override
                public int compare(MyLink ctaLink1,MyLink ctaLink2)
                {
                    return ctaLink1.getOrder() - ctaLink2.getOrder();
                }
            });
    
            
            
        }
    
    
    }

Please suggest how I can sort the list of profile on enum order

Answer 1

You are trying to sort a List of Profile but your Comparator compares MyLink - not Profile. The Comparator should be something like (not tested):

new Comparator<Profile>() {
    @Override
    public int compare(Profile ctaLink1, Profile ctaLink2) {
        return ctaLink1.getEligibilityType().getOrder() - ctaLink2.getEligibilityType().getOrder();
    }
}

Of course for sake of clarity you should have a Profile Comparator that forwards to your MyLink Comparator