https://www.youtube.com/watch?v=nMiS5ZRSgCw&t=574s Object-Oriented Programming, OOP package projectOOP; import java.io.FileWriter; import java.io.IOException; public class othersOOP { public static void main(String[] args) throws IOException { //throws IOException는 Filewriter의 예외처리 관련 코드 // class : System, math, Filewriter // instance : f1, f2 System.out.println(Math.PI); System.out.println(Math..