Выкидывает NullPoinException на втором примере
package com.javarush.task.task30.task3001;
public class Number {
private NumberSystem numberSystem;
private String digit;
public Number(NumberSystem numberSystem, String digit) {
this.numberSystem = numberSystem;
this.digit = digit;
}
public NumberSystem getNumberSystem() {
return numberSystem;
}
public String getDigit() {
return digit;
}
@Override
public String toString() {
return "Number{" +
"numberSystem=" + numberSystem +
", digit='" + digit + '\'' +
'}';
}
}