Answer

Answer

아래코드와 반드시 동일해야하만 정답은 아닙니다. 문제를 만들면서 생각했던 방향성일뿐 해결하는 방식은 다양할 수 있으니, 참고만 해주시면 좋겠습니다.

• Object

  @Override
  public boolean equals(Object obj) {
      if (obj == null)
          return false;
      if (this == obj)
          return true;
      if (obj instanceof Person) {
          return ((Person) obj).getId().equals(this.getId());
      }
      return false;
  }
  
  @Override
  public int hashCode() {
      return Objects.hash(id);
  }

• Collection

  • Comparable

    @Override
    public int compareTo(Car o) {
        // TODO Auto-generated method stub
        int modelCompare = this.getModel().compareTo(o.getModel());
        if (modelCompare != 0) {
            return modelCompare;
        }
    
        int priceCompare = o.getPrice()- this.getPrice();
        if (priceCompare != 0) {
            return priceCompare;
        }
    
        return this.getSpeed()- o.getSpeed();
    }

  • Comparator

    PriorityQueue<Car> cars = new PriorityQueue<>((c1, c2) -> {
        int priceCompare = c2.getPrice() - c1.getPrice();
        if (priceCompare != 0) {
            return priceCompare;
        }
    
        int modelCompare = c2.getModel().compareTo(c1.getModel());
        if (modelCompare != 0) {
            return modelCompare;
        }
    
        return c1.getSpeed() - c2.getSpeed();
    });

• Exception

  • checkAge

    public void checkAge(int age) throws Exception {
        if (age < 18) {
            throw new InvalidAgeException("나이는 18세 이상이어야 합니다.");
        }
        System.out.println("나이 검증 통과!");
    }

  • checkAgeResult

    public void checkAgeResult(int age) {
        try {
            checkAge(age);
        } catch (Exception e) {
            // Code
        }
    }

  • unchecked

    public void divide(int n) {
        try {
            int i = 10 / n;
        } catch (Exception e) {
    
        }
    }

• File IO

  • Book

    public class Book implements Serializable {
        private String title;
        private String author;
        private String isbn;
        private int price;
        private transient String ssn;
    }