Как запихнуть массив в файл?

package Package3;
 
 
import java.util.Scanner;
import java.util.Random; 
 
class Student { 
@SuppressWarnings("unused") 
private int id; 
 
public Student(int id) { 
this.id = id; 
} 
 
private students[] student; 
private Kurs[] kurs; 
private Prepod[] prepod; 
 
class students { 
private String namestudents; 
 
public students(String namestudents) { 
this.namestudents = namestudents; 
} 
 
String getnamestudents() { 
return namestudents; 
} 
} 
 
class Kurs { 
private String nameKurs; 
 
public Kurs(String nameKurs) { 
this.nameKurs = nameKurs; 
} 
 
String getnameKurs() { 
return nameKurs; 
} 
} 
 
public void setstudents(String[] namestudents) { 
student = new students[namestudents.length]; 
for (int i = 0; i < namestudents.length; i++) 
student[i] = new students(namestudents[i]); 
} 
 
void showT() { 
for (int i = 0; i < student.length; i++) { 
System.out.println(student[i].getnamestudents()); 
} 
} 
 
public void setKurs(String[] nameKurs) { 
kurs = new Kurs[nameKurs.length]; 
for (int i = 0; i < nameKurs.length; i++) 
kurs[i] = new Kurs(nameKurs[i]); 
} 
 
void showA() { 
for (int i = 0; i < kurs.length; i++) { 
System.out.println(kurs[i].getnameKurs()); 
} 
} 
 
class Prepod { 
private String namePrepod; 
 
public Prepod(String namePrepod) { 
this.namePrepod = namePrepod; 
} 
 
String getnamePrepod() { 
return namePrepod; 
} 
} 
 
public void setPrepod(String[] namePrepod) { 
prepod = new Prepod[namePrepod.length]; 
for (int i = 0; i < namePrepod.length; i++) 
prepod[i] = new Prepod(namePrepod[i]); 
} 
 
void showD() { 
for (int i = 0; i < prepod.length; i++) { 
System.out.println(prepod[i].getnamePrepod()); 
} 
} 
 
} 
 
public class Fakultativ { 
private static int Random(int i) { 
Random rand = new Random(); 
int sa = (Math.abs(rand.nextInt()) % i) + 1; 
return sa; 
} 
 
@SuppressWarnings("resource")
public static void main(String[] args) { 
   
String a, dr,t; 
 
Student d = new Student(1); 
System.out.println("Выберите студента:"); 
String student[] = { "Ivanov" , "Petrov", "Sidorov" }; 
d.setstudents(student); 
d.showT(); 
Scanner in1 = new Scanner(System.in); 
t = in1.next(); 
System.out.println("Выбран студент:" + t); 
boolean statestudents = false; 
System.out.println("Выберите курс:"); 
String kurs[] = { "Math", "Fizika", "Proga", "Pravo", "SpecGlav" }; 
d.setKurs(kurs); 
d.showA(); 
Scanner in2 = new Scanner(System.in); 
a = in2.next(); 
System.out.println("Выбран курс:" + a); 
System.out.println("Выберите преподователя:"); 
 
if (a.equals("Math")){
String prepod[] = { "Petrov", "Leonidov"}; 
d.setPrepod(prepod); 
d.showD(); }
if (a.equals("Fizika")){
String prepod[] = { "Sidorov", "Semenov"}; 
d.setPrepod(prepod); 
d.showD(); }
if (a.equals("Proga")){
String prepod[] = { "Molodcov", "Antoshkin"}; 
d.setPrepod(prepod); 
d.showD(); }
if (a.equals("Pravo")){
String prepod[] = { "Klimov", "Fedorov"}; 
d.setPrepod(prepod); 
d.showD(); }
if (a.equals("SpecGlav")){
String prepod[] = { "Vorobev", "Solodenko"}; 
d.setPrepod(prepod); 
d.showD(); }
Scanner in3 = new Scanner(System.in); 
dr = in3.next(); 
System.out.println("Выбран преподаватель:" + dr); 
int s;
s = Random(5); 
if (s==1) {
System.out.println("1"); }
if (s==2) {
System.out.println("2"); }
if (s==3) {
System.out.println("3"); }
if (s==4) {
System.out.println("4"); }
if (s==5) {
System.out.println("5"); }
 
 
 
}}