//import java.util.*;

class Exception1{

	public static void main(String args[]) {

		try{

			AClass ac = new AClass();
			ac.setAge(18);
			System.out.println(ac.toString());

			try{

				exTest(-18);

			}catch(IllegalArgumentException ie) {
				ie.printStackTrace();

			}/*catch(AgeLessThanZeroException ae) {
				ae.printStackTrace();

			}//catch
			*/
		}catch(Exception e){

		}

	}//main

	public static void exTest(int age) {
		//try{
			if(age < 0)
				throw new IllegalArgumentException("Has to be positive.");
			else
				System.out.println("The age is = " + age);
		/*
		}catch(IllegalArgumentException ie){
			ie.printStackTrace();
		}//catch
		*/
	}//exText()

}//Exception1


class AClass{

	private int age;

	AClass(){}
	AClass(int age){

		this.age = age;

	}//constructor


	public void setAge(int newage)/* throws AgeLessThanZeroException*/{

		if(newage < 0){
			throw new AgeLessThanZeroException("Age cannot be less than zero.");
		}//if
		else
			this.age = newage;


	}//setAge

	public String toString(){
		return "Age = " + age;
	}//toString()

}//AClass

class AgeLessThanZeroException extends RuntimeException{ // if extends Exception --> need to have throws in the method

	public AgeLessThanZeroException(String message){
		super(message);
		System.out.println(message);
	}

}//AgeLessThanZeroException