I cant understand
package com.codegym.task.task20.task2011;
/*
Externalizable for apartments
*/
import java.io.Externalizable;
import java.io.ObjectInput;
public class Solution {
public static abstract class Apartment implements Externalizable, writeExternal {
private String address;
private int year;
/**
* Mandatory public no-arg constructor.
*/
public Apartment() { super(); }
public Apartment(String addr, int y) {
address = addr;
year = y;
}
/**
* Prints out the fields used for testing!
*/
public String toString() {
return("Address: " + address + "\n" + "Year: " + year);
}
}
public static void main(String[] args) {
}
}