How to sort LinkedLists using compareTo in java8

Question

I need to sort a linked list of StudentInfo objectsx using compareTo().

This is my StudentInfo clas

package mahaffy_lab4;
import java.util.*;
/**
 *
 * @author student
 */

 public class StudentInfo implements Comparable<StudentInfo>
 {

private LinkedList<Object> classes = new LinkedList<>();
private String sid, name;


public StudentInfo(String sid, String name)
{
    this.sid = sid;
    this.name = name;

}

public void AddClass(Object aClass)
{       
   classes.add(aClass);
}
@Override
public int compareTo(StudentInfo studentA)
{

    return this.name.compareTo(student.name);
}
@Override    
public String toString()
{
    return "Name: " + name + "   SID: " + sid;
}

}

But this is where my issue is. in my main/test class, nothing i have tried works. this is the last try I made:

private LinkedList<Object> students = new LinkedList<>();

public String GetAllStudents()
 {   

     Collections.sort(students, new Comparator<String>() {
         @Override
         public int compare(StudentInfo o1, StudentInfo o2) {
            return Collator.getInstance().compare(o1, o2);
         }            
     });   

     return students.toString();
 }

Please, any help would be appreciated.

Answer 1

The problem is in the declaration:

private LinkedList<Object> students = new LinkedList<>();

LinkedList is a list of Object, so values of the list are compared as Object, not as StudentInfo.

To fix the problem, re-declare the list:

private LinkedList<StudentInfo> students = new LinkedList<>();