¿Cómo arreglar java.lang.ClassCastException en TreeSet usando un comparador personalizado en Java?

Java

// Java program to fix java.lang.ClassCastException
// in TreeSet using Comparator
  
import java.util.Comparator;
import java.util.TreeSet;
  
class friendsMarks {
    // class field
    String name;
    String nickName;
    int marks;
  
    // parameterised constructor
    public friendsMarks(String name, String nickName,
                        int marks)
    {
        this.name = name;
        this.nickName = nickName;
        this.marks = marks;
    }
  
    // getter for name
    public String getName() { return name; }
  
    // setter for name
    public void setName(String name) { this.name = name; }
  
    // getter for marks
    public int getMarks() { return marks; }
  
    // setter for marks
    public void setMarks(int marks) { this.marks = marks; }
  
    // getter for nickname
    public String getNickName() { return nickName; }
  
    // setter for nickname
    public void setNickName(String nickName)
    {
        this.nickName = nickName;
    }
  
    //@Override toString method
    public String toString()
    {
        return "friendsMarks{"
            + "name='" + name + '\'' + ", nickName='"
            + nickName + '\'' + ", marks=" + marks + '}';
    }
}
  
// for comparing names
class nameCompare implements Comparator<friendsMarks> {
  
    @Override
    public int compare(friendsMarks friend1,
                       friendsMarks friend2)
    {
        return friend1.getName().compareTo(
            friend2.getName());
    }
}
  
// for comparing marks
class marksCompare implements Comparator<friendsMarks> {
  
    @Override
    public int compare(friendsMarks f1, friendsMarks f2)
    {
        if (f1.getMarks() > f2.getMarks()) {
            return 1;
        }
        else {
            return -1;
        }
    }
}
  
// for comparing nick name
class nickNameCompare implements Comparator<friendsMarks> {
  
    @Override
    public int compare(friendsMarks obj1, friendsMarks obj2)
    {
        return obj1.getNickName().compareTo(
            obj2.getNickName());
    }
}
public class Main {
  
    public static void main(String[] args)
    {
  
        // Creating TreeSet
        // and we have to pass Comparator object
        // of marksCompare class
        // in the TreeSet constructor
        // so that we can sort according to the marks
        TreeSet<friendsMarks> treeSet
            = new TreeSet<>(new marksCompare());
  
        // adding elements to TreeSet
        treeSet.add(new friendsMarks("Raushan", "Chamgader", 99));
        treeSet.add(new friendsMarks("Yashdeep", "Dopa", 95));
        treeSet.add(new friendsMarks("Rupesh", "Gian", 92));
        treeSet.add(new friendsMarks("Shivam", "Gorilla", 47));
        treeSet.add(new friendsMarks("Sarthak", "Nagin", 78));
        treeSet.add(new friendsMarks("Sonika", "Chipkali", 67));
        treeSet.add(new friendsMarks("Himanshu", "Lalten", 57));
  
        System.out.println("Sorting on the basis of marks");
  
        // Displaying using loop
        for (friendsMarks tree : treeSet)
            System.out.println(tree);
  
        // Creating TreeSet
        // and we have to pass Comparator object
        // of nameCompare class
        // in the TreeSet constructor
        // so that we can sort according to the name
        TreeSet<friendsMarks> treeSet1
            = new TreeSet<>(new nameCompare());
  
        // adding elements to TreeSet
        treeSet1.add(new friendsMarks("Raushan", "Chamgader", 99));
        treeSet1.add(new friendsMarks("Yashdeep", "Dopa", 95));
        treeSet1.add(new friendsMarks("Rupesh", "Gian", 92));
        treeSet1.add(new friendsMarks("Shivam", "Gorilla", 47));
        treeSet1.add(new friendsMarks("Sarthak", "Nagin", 78));
        treeSet1.add(new friendsMarks("Sonika", "Chipkali", 67));
        treeSet1.add(new friendsMarks("Himanshu", "Lalten", 57));
  
        // Displaying using loop
        System.out.println("\n\nSorting on the basis of name");
  
        for (friendsMarks tree : treeSet1)
            System.out.println(tree);
  
        // Creating TreeSet
        // and we have to pass Comparator object
        // of nickNameCompare class
        // in the TreeSet constructor
        // so that we can sort according to the nickname
        TreeSet<friendsMarks> treeSet2
            = new TreeSet<>(new nickNameCompare());
  
        // adding elements to TreeSet
        treeSet2.add(new friendsMarks("Raushan", "Chamgader", 99));
        treeSet2.add(new friendsMarks("Yashdeep", "Dopa", 95));
        treeSet2.add(new friendsMarks("Rupesh", "Gian", 92));
        treeSet2.add(new friendsMarks("Shivam", "Gorilla", 47));
        treeSet2.add(new friendsMarks("Sarthak", "Nagin", 78));
        treeSet2.add(new friendsMarks("Sonika", "Chipkali", 67));
        treeSet2.add(new friendsMarks("Himanshu", "Lalten", 57));
  
        // Displaying using loop
        System.out.println("\n\nSorting on the basis of nick-name");
  
        for (friendsMarks tree : treeSet2)
            System.out.println(tree);
    }
}