Java Objects & Classes Quiz 6
The quiz below tests your knowledge of the material learnt in Objects & Classes - Lesson 6 - Methods - Passing Values.
Question 1 : We pass objects to methods as arguments?
- We DO NOT pass objects to methods as arguments, we actually pass a copy of the reference variable associated with that object.
Question 2 : What will be output from this code snippet?
package info.java8;
public class Dog {
String name;
void dogLooks(String name) {
name = "zzz";
}
}
package info.java8;
public class TestDog {
public static void main (String[] args) {
Dog doggy = new Dog();
String name = "rover";
doggy.dogLooks(name);
System.out.println("Our dog is called: " + name);
}
}
- The output will be <code>Our dog is called: rover</code> as we are passing a copy of the name parameter, the original remains unchanged and is printed on return.
Question 3 : Where are objects stored?
- Objects are stored on the <code>heap</code>.
Question 4 : We pass primitives to methods as arguments?
- We DO NOT pass primitives to methods as arguments, we actually pass a copy of the value associated with that primitive.
Question 5 : What will be output from this code snippet?
package info.java8;
public class Dog {
String name;
void dogLooks(Dog dog) {
dog.name = "zzz";
}
}
package info.java8;
public class TestDog {
public static void main (String[] args) {
Dog doggy = new Dog();
doggy.name = "rover";
doggy.dogLooks(doggy);
System.out.println("Our dog is called: " + name);
}
}
- The output will be <code>Our dog is called: zzz</code>; although we are passing a copy of the reference variable we are still updating the actual <code>Dog</code> object on the heap, so the original is changed and is printed on return.
Question 6 : When we pass an argument to a method what are we are actually passing?
- When we pass an argument to a method we are actually passing a copy of the argument and this is known as <i>pass-by-value</i>
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What's Next?
The in our final quiz on Java methods we test your knowledge of overloading and variable arguments.
