ArrayList - "Unchecked or unsafe operations" at compile

[beachwood23]

I have written the following program using an ArrayList.

import java.util.ArrayList;
 
public class TestArrayList {
	public static void main(String[] args) {
		//create a list to store cities
		ArrayList cityList = new ArrayList();
		
		//add some cities to the list
		cityList.add("London");
		//citylist now contains [London]
		cityList.add("Denver");
		cityList.add("Paris");
		cityList.add("Timbuktu");
		cityList.add("Burlington");
		cityList.add("Dublin");
		cityList.add("Miami");
		cityList.add("Tokyo");
		//cityList now contains[London,Denver,Paris,Timbuktu,Burlington, Dublin,Miami,Tokyo]
		
		System.out.println("list size " + cityList.size());
		System.out.println("is miami in the list? " + cityList.contains("Miami"));
		System.out.println("location of denver in the list " + cityList.indexOf("Denver"));
		System.out.println("Is the list empty " + cityList.isEmpty());
		
		//insert new city at index 2
		cityList.add(2, "Xian");
		//remove a city from the list
		cityList.remove("Miami");
		//remove city at index 1
		cityList.remove(1);
		//display contents in the list
		System.out.println(cityList.toString());
		
		//display contents in reverse order
		for (int i = 0; i < cityList.size(); i++) {
			System.out.println(cityList.get(i) + " ");
		}
		
		//create a list to store two circle
		ArrayList list = new ArrayList();
		
		//add two circles
		list.add(new Circle4(2));
		list.add(new Circle4(3));
		
		//display area of first circle in list
		System.out.println("\nthe area of the circle? " + ((Circle4)list.get(0)).getArea());
	}
}

When I try to compile, I have "unchecked or unsafe operations." I compiled it with the suggested -Xlint:unchecked parameter, and there are 11 errors: on all of the <ArrayList>.add(<item>).Does anyone know what I need to change, or what I'm doing wrong?

Thanks

[Fubarable]

Look at the messages carefully -- they're warnings, not errors, and that's a big difference. They're warning you that you're not using generics with your ArrayList, and if you don't need to use generics, you can ignore them.

In the future, you'll want to post your entire error messages here rather than paraphrasing them so we will have no doubt as to your exact error message.