macOS java: what is wrong with my sorting algorithms / comparator / compareTO?

package project2;
import java.util.*;
import java.text.DecimalFormat;
/**
 *
 * @author Kevin
 */
public class Scholar implements Comparable {
    // private variables
    private String fullName;
    private double gradePointAverage;
    private int essayScore;
    private int creditHours;
    private boolean scienceMajor;
    private boolean selected;
    private double totalScore;
    private DecimalFormat fmt;

       // constructor for a Scholar object
        public Scholar(String myFullName, double myGradePointAverage, int myEssayScore,
                       int myCreditHours, boolean isScienceMajor){
                this.fullName = myFullName;
                this.gradePointAverage = myGradePointAverage;
                this.essayScore = myEssayScore;
                this.creditHours = myCreditHours;
                this.scienceMajor = isScienceMajor;

                selected = false; // in case selected for a Scholar object is already set to true.

        }
        // returns a Scholar object's fullname
        public String getFullName(){
            return fullName;
        }
        // returns a Scholar object's gpa
        public double getGradePointAverage(){
            return gradePointAverage;
        }
        // returns a Scholar object's essay score
        public int getEssayScore(){
            return essayScore;
        }
        /// returns a Scholar object's credit hours
        public int getCreditHours(){
            return creditHours;
        }
        // retruns if a Scholar object is a science major or not
        public boolean getScienceMajor(){
            return scienceMajor;
        }
        // sets a Scholar object's full name
        public String setFullName(String fullName){
           return fullName;
        }
        // sets a Scholar object's gpa
        public double setGradePointAverage(double a){
            gradePointAverage = a;
            return gradePointAverage;
        }
        // sets a Scholar object's gpa
        public int setEssayScore(int a){
            essayScore = a;
            return essayScore;
        }
        // sets a Scholar object's credit hours
        public int setCreditHours(int a){
            creditHours = a;
            return creditHours;
        }
        // sets a Scholar's major to a science major or not a science major
        public boolean setScienceMajor(boolean a){
            scienceMajor = a;
            return scienceMajor;
        }

        // calculates a Scholar object's score
        public double getScore(){
            totalScore = (gradePointAverage*5) + essayScore;
            if (scienceMajor == true)
                totalScore += .5;
            if (creditHours >= 60 && creditHours <90)
                totalScore += .5;
            else if (creditHours >= 90)
                totalScore += .75;
            return totalScore;
        }
        public String reverseFullName(){
            int num = 0;
            for (int i = 0; i < fullName.length(); i++){
                if (fullName.charAt(i) ==  ' ')
                num = i + 1;
            }

            String temp;
            String temp2;
            temp = fullName.substring(0, num);
            temp2 = fullName.substring(num);
            String fullName2 = (temp2 + ", " +  temp);
            return fullName2;
        }
        // compares two scholar objects.
        public int compareTo(Object obj){
            Scholar otherObj = (Scholar)obj;
            double result = getScore() - otherObj.getScore();
            if (result > 0)
                return 1;
            else if (result < 0)
                return -1;
            return 0;
        }
       /* public int compareTo(Scholar s){// dont know
            String otherReverseFullName = s.getFullName();
            if(otherReverseFullName.equals())

        }
        */
        // returns the highest scoring of two Scholar objects
        public static Scholar max(Scholar s1, Scholar s2){
            if (s1.getScore() > s2.getScore())
                System.out.println(s1.getFullName() + " scored higher than " +
                                   s2.getFullName() + ".\n");
            else
               System.out.println(s2.getFullName() + " scored higher than " +
                                   s1.getFullName() + ".\n");
            return null;
        }
        // returns the highest of 3 student objects
        public static Scholar max(Scholar s1, Scholar s2, Scholar s3){
            if (s1.getScore() > s2.getScore() && s1.getScore() > s3.getScore())
                System.out.println(s1.getFullName() + " scored the highest" +
                        " out of all three students.");
            else if (s2.getScore() > s1.getScore() && s2.getScore() > s3.getScore())
                System.out.println(s2.getFullName() + " scored the highest" +
                        " out of all three students.");
            else if (s3.getScore() > s2.getScore() && s3.getScore() > s1.getScore())
                System.out.println(s3.getFullName() + " scored the highest" +
                        " out of the three students.");
            return null;
        }
        public void setSelection(boolean f){// dont know
            selected = f;
        }
        public boolean isSelected(){
            return selected;
        }
        

        // toString method for a Scholar object
        public String toString(){
            // new decimal format used to change the format of the double gradePointAverage.
            DecimalFormat fmt = new DecimalFormat("0.###");
            return  "Student name: " + reverseFullName() + "-" + " Grade Point Average: "
                    + fmt.format(gradePointAverage)  + ". " + "Essay Score: " + essayScore + "."
                    + " Credit Hours: " + creditHours + ". "  +  " Science major: " +
                     scienceMajor + ". ";//Scholarship Selection: " + selected + ".";

        }

}

/*
 * Scholarship.java
 *
 * Created on March 20, 2007, 20071:40 AM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package project2;
import java.util.*;

/**
 *
 * @author Kevin
 */
public class Scholarship implements Comparator {
    private String scholarship;
    private double amount;
    private int intendedNumberAwarded;
    private int actualNumberAwarded;
    private Scholar [] scholar;
    private int numberApplicants;
    public static final int MAX_DEFAULT = 5;
    
    /** Creates a new instance of Scholarship */
    public Scholarship(String scholarship, double amount, int number) {
        this.scholarship = scholarship;
        this.amount = amount;
        this.intendedNumberAwarded = number;
        this.actualNumberAwarded = 0;

        scholar = new Scholar[MAX_DEFAULT];

    }

     public String getScholarShipName(){
         return scholarship;
     }
     public String getNumApplicants(){// why is this not an int
         return String.valueOf(numberApplicants);
     }
     public double getSingleScholarshipAmount(){
         return amount;
     }
     public int getNumberWinners(){
         for(int i = 0; i < scholar.length; i ++){
     if(scholar[i]instanceof Scholar && scholar[i].isSelected()==true)
        actualNumberAwarded++;
     }
     actualNumberAwarded -= 1; 
     
     return actualNumberAwarded;
     }
     public double getAmountAwarded(){
         amount = amount/getNumberWinners();
             /*for(int i = 0; i < scholar.length; i ++){
             getNumberWinners();

         }
             */
            return amount;
     }
     public boolean addApplicant(Scholar s){

         boolean f = false;
         for(int i = 0; i < scholar.length; i++){
// or if(scholar[i]!=null]
             if(scholar[i] instanceof Scholar) {}
             else {
                 f = true;
                 scholar[i] = s;

                break;
             }
         }

         if(!f){
             Scholar[] temp = new Scholar[scholar.length * 2];
             int x = 0;
             for (int j = 0; j < scholar.length; j++) {
                 temp[j] = scholar[j];
                 x = j;
             }
             temp[x] = s;
             scholar = temp;
         }

         return true;
     }
     public void printAllApplicantsByScore(){
        StringBuffer buf2 = new StringBuffer(
                 "\nScholarship = " + scholarship + 
                //" Amount that will be awarded among winners = " + getSingleScholarshipAmount() +
                 ". Number of intended winners = " + intendedNumberAwarded);

         buf2.append("\n------------------------------\n"); 
         int min;
         Scholar temp;
         for (int index =0 ; index < scholar.length; index++)
        {
            min = index;
                for(int scan = index + 1; scan < scholar.length; scan++)
                    if(scholar[scan].compareTo(scholar[min]) == 0.0)
                        min = scan;
            // swap
            temp = scholar[min];
            scholar[min] = scholar[index];
            scholar[index] = temp;
            //if(scholar[index]!=null)
   
                buf2.append ("["  + (index+1) + "]:" + scholar[index] + "\n");
        }
        System.out.println(buf2);
     }
	public int compare(Object o1, Object o2) {
		Scholar s1 = (Scholar)o1;
		Scholar s2 = (Scholar)o2;
		int i = 0;
		int name = s1.reverseFullName().compareTo(s2.reverseFullName());
               return ((name == 0) ? s1.reverseFullName().compareTo(
        s2.reverseFullName()) : name);
                    
	}
 


     public void printAllApplicantsByName(){
        StringBuffer buf2 = new StringBuffer(
                 "\nScholarship = " + scholarship + 
                //" Amount that will be awarded among winners = " + getSingleScholarshipAmount() +
                 ". Number of intended winners = " + intendedNumberAwarded);

         buf2.append("\n------------------------------\n"); 
         
         int min;
         Scholar temp;
         for (int index =0 ; index < scholar.length; index++)
        {
            min = index;
                for(int scan = index + 1; scan < scholar.length; scan++)
                    if(compare(scholar[scan], scholar[min]) == 0)
                        min = scan;
            // swap
            temp = scholar[min];
            scholar[min] = scholar[index];
            scholar[index] = temp;
            //if(scholar[index]!=null)
            
        buf2.append ("["  + (index+1) + "]:" + scholar[index] + "\n");
         }
        System.out.println(buf2);
     }


     public String toString(){
         amount = amount/getNumberWinners();
         System.out.println("The winners are:");
         StringBuffer buf = new StringBuffer(
                 "\nScholarship = " + scholarship + ". Amount Awarded = " + getAmountAwarded() +
                 ". Number of Winners = " + (getNumberWinners() - 1));

         buf.append("\n------------------------------\n");
        for (int i =0 ; i < scholar.length; i ++)
        {
            if(scholar[i]!=null && scholar[i].isSelected())
                buf.append ("[" + (i+1) + "]:" + scholar[i] + "\n");
        }
          return buf.toString();
     }

}

/*
 * ScholarShipTester.java
 *
 * Created on March 20, 2007, 1:46 AM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package project2;

public class ScholarShipTester {

    public static void main(String [] args){

    Scholar a = new Scholar("Jane Doe", 2.1, 3, 34, false);
    boolean f = true;
    boolean b = true;
    Scholar john = new Scholar("John Doe", 3.67, 4, 43, b);
    System.out.println(kevin.isSelected());// remove
    john.setSelection(true);
    a.setSelection(true);
    System.out.println(john.isSelected());// remove;
    //a.setSelection(true);
    //john.setSelection(b);
    //System.out.println(a);
    //System.out.println(a.getScore());
    Scholarship s1 = new Scholarship("Presidential", 500.00, 2);
    s1.addApplicant(john);
    s1.addApplicant(a);
    System.out.println(s1);
    s1.printAllApplicantsByName();
   //s1.printAllApplicantsByScore();
    }
}

     public void printAllApplicantsByScore(){
        StringBuffer buf2 = new StringBuffer(
                 "\nScholarship = " + scholarship + 
                //" Amount that will be awarded among winners = " + getSingleScholarshipAmount() +
                 ". Number of intended winners = " + intendedNumberAwarded);
                 //Arrays.sort(scholar, Comparator c);
         buf2.append("\n------------------------------\n");
                 
                     
                 //scholar = insertionSort(scholar);
         Scholar nullScholar = new Scholar("Jon Smith", 0.0, 0, 0, false);
         int min;
         Scholar temp;
         for (int index =0 ; index < scholar.length; index++)
        {
            min = index;
            
                for(int scan = index + 1; scan < scholar.length; scan++){
                    if(scholar[index] == null || scholar[min] == null || scholar[scan] == null)
                        //scholar[index] = nullScholar;
                        scholar[scan] = nullScholar;
                    if(scholar[scan].compareTo(scholar[min]) > 0)
                        min = scan;
                }
            
            // swap
            temp = scholar[min];
            scholar[min] = scholar[index];
            scholar[index] = temp;
            
                if(scholar[index] != nullScholar)
                buf2.append ("["  + (index+1) + "]:" + scholar[index].getFullName() + 
                       " scored " +  scholar[index].getScore() + "\n");
        }
        System.out.println(buf2);
     }