public class Student1 implements Comparable<Student1> {
    private String name;
    private int kor;
    private int eng;
    private int math;

    public Student1(String name, int kor, int eng, int math) {
        this.name = name;
        this.kor = kor;
        this.eng = eng;
        this.math = math;
    }

    public Student1() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getKor() {
        return kor;
    }

    public void setKor(int kor) {
        this.kor = kor;
    }

    public int getEng() {
        return eng;
    }

    public void setEng(int eng) {
        this.eng = eng;
    }

    public int getMath() {
        return math;
    }

    public void setMath(int math) {
        this.math = math;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Student1 student1 = (Student1) o;

        if (kor != student1.kor) return false;
        if (eng != student1.eng) return false;
        if (math != student1.math) return false;
        return name != null ? name.equals(student1.name) : student1.name == null;
    }

    @Override
    public int hashCode() {
        int result = name != null ? name.hashCode() : 0;
        result = 31 * result + kor;
        result = 31 * result + eng;
        result = 31 * result + math;
        return result;
    }

    @Override
    public String toString() {
        return "Student1{" +
                "name='" + name + '\'' +
                ", kor=" + kor +
                ", eng=" + eng +
                ", math=" + math +
                '}';
    }

    @Override
    public int compareTo(Student1 o) {
        return name.compareTo(o.name);
    }
}

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

public class StudentExam1 {
    public static void main(String args[]) {
        Student1 s1 = new Student1("Kim", 70, 60, 80);
        Student1 s2 = new Student1("Jang", 85, 55, 90);
        Student1 s3 = new Student1("Lee", 80, 50, 70);

        List<Student1> slist = new ArrayList<>();
        slist.add(s1);
        slist.add(s2);
        slist.add(s3);

        System.out.println("*insert");
        for (Student1 student : slist) {
            System.out.println(student);
        }
        System.out.println();

        System.out.println("*Name");
        Collections.sort(slist);
        for (Student1 student : slist) {
            System.out.println(student);
        }
        System.out.println();

        System.out.println("*Kor");
        Collections.sort(slist, new NewStudentKoreanComparator());
        for (Student1 student : slist) {
            System.out.println(student);
        }
        System.out.println();

        System.out.println("*Eng");
        Collections.sort(slist, new NewStudentEnglishComparator());
        for (Student1 student : slist) {
            System.out.println(student);
        }
        System.out.println();

        System.out.println("*Math");
        Collections.sort(slist, new NewStudentMathComparator());
        for (Student1 student : slist) {
            System.out.println(student);
        }

    }
}

class NewStudentKoreanComparator implements Comparator<Student1> {
    @Override
    public int compare(Student1 o1, Student1 o2) {
        return o1.getKor() - o2.getKor();
    }
}

class NewStudentEnglishComparator implements Comparator<Student1> {
    @Override
    public int compare(Student1 o1, Student1 o2) {
        return o1.getEng() - o2.getEng();
    }
}

class NewStudentMathComparator implements Comparator<Student1> {
    @Override
    public int compare(Student1 o1, Student1 o2) {
        return o1.getMath() - o2.getMath();
    }
}