public class Demo3 { public static void main(String[] args) { Circle circle1 = new Circle(4); int x = 4; System.out.println( circle1.getRadius() + " " + x ); // 4 4 incrementRadius( circle1 ); // Pass a reference type variable incrementInt( x ); // Pass a primitive type var System.out.println( circle1.getRadius() + " " + x); // 5 4 } // Method updates object passed as parameter public static void incrementRadius( Circle c ) { c.radius++; // Increment c.radius by 1 } // Method updates int passed as parameter public static void incrementInt( int c ) { c++; // Increment c by 1 } }