Questions and Exercises: Objects
Questions
-
What's wrong with the following program?
public class SomethingIsWrong { public static void main(String[] args) { Rectangle myRect; myRect.width = 40; myRect.height = 50; System.out.println("myRect's area is " + myRect.area()); } }
-
The following code creates one array and one string object. How many references to those objects exist after the code executes? Is either object eligible for garbage collection?
... String[] students = new String[10]; String studentName = "Peter Parker"; students[0] = studentName; studentName = null; ...
-
How does a program destroy an object that it creates?
Exercises
-
Fix the program called
SomethingIsWrong
shown in Question 1. -
Given the following class, called
NumberHolder
, write some code that creates an instance of the class, initializes its two member variables, and then displays the value of each member variable.public class NumberHolder { public int anInt; public float aFloat; }