JavaScript and Java Programming Quiz

Test your knowledge of JavaScript objects, functions, and Math operations, along with Java inner classes including nested classes and anonymous inner classes.

15 Questions Published

Play Quiz Practise this topic out loud

Questions

Question 1 Multiple Choice (Single Answer)

Which is true about an anonymous inner class?

It can extend exactly one class and implement exactly one interface.
It can extend exactly one class and can implement multiple interfaces.
It can extend exactly one class or implement exactly one interface.
It can implement multiple interfaces regardless of whether it also extends a class.

Question 2 Multiple Choice (Single Answer)

class Boo {
    Boo(String s) {}
    Boo() {}
}
class Bar extends Boo {
    Bar() {}
    Bar(String s) {
        super(s);
    }
    void zoo() { 
         // insert code here      
    }  
}

which one create an anonymous inner class from within class Bar?

Boo f = new Boo(24) { };
Boo f = new Bar() { };
Bar f = new Boo(String s) { };
Boo f = new Boo.Bar(String s) { };

Question 3 Multiple Choice (Single Answer)

Which is true about a method-local inner class?

It must be marked final.
It can be marked abstract.
It can be marked public.
It can be marked static.

Question 4 Multiple Choice (Single Answer)

Which constructs an anonymous inner class instance?

Runnable r = new Runnable() { };
Runnable r = new Runnable(public void run() { });
Runnable r = new Runnable { public void run(){}};
System.out.println(new Runnable() {public void run() { }});

Question 5 Multiple Choice (Single Answer)

public class MyOuter {
    public static class MyInner {
        public static void foo() {}
    }
}

which statement, if placed in a class other than MyOuter or MyInner, instantiates an instance of the nested class?

MyOuter.MyInner m = new MyOuter.MyInner();
MyOuter.MyInner mi = new MyInner();
MyOuter m = new MyOuter(); MyOuter.MyInner mi = m.new MyOuter.MyInner();
MyInner mi = new MyOuter.MyInner();

Question 6 Multiple Choice (Single Answer)

What is the output of the below JavaScript?
alert(Math.sqrt(-16));

-4
4
Error
NaN

Question 7 Multiple Choice (Single Answer)

What is the output of the below JavaScript?

<script>  		
with(Math){  			  
     alert(pow(2,3));  		
}  	
</script>

8
9
error
6

Question 8 Multiple Choice (Single Answer)

What is the output of the below JavaScript?

<script>  		
alert(parseInt("8.56") + " " + parseInt("8error"));  	
</script>

Error
98
88
16

Question 9 Multiple Choice (Single Answer)

What is the output of the below JavaScript?
alert(parseFloat("8.56"));

8.56
9
error
NaN

Question 10 Multiple Choice (Single Answer)

What is the output of the below JavaScript?

<script>
    var currDate = new Date("30 September, 2011");
    alert(currDate.getMonth());
</script>

9
8
10
error

Question 11 Multiple Choice (Single Answer)

<script>  		
function Book(id, name) {
    this.id = id;
    this.name = name;
}
var book = new Book("1001", "Head First JavaScript");
alert(book.id);
</script>

1001
error
Head First JavaScript
id

Question 12 Multiple Choice (Single Answer)

What is the output of the below JavaScript?

<script>  		
var book = "Head First JavaScript";  		
alert(book.length);  	
</script>

21
20
22
error

Question 13 Multiple Choice (Single Answer)

<script>  		
a = 10;  		
var b = 20;  		
var c = a + b;  		
alert(c);  	
</script>

error
1020
30
20

Question 14 Multiple Choice (Single Answer)

<script>  		
var personObj = new Object();  		
personObj.firstname = "Jerome";  		
personObj.lastname = "Davin";  		
alert(personObj.firstname);  	
</script>

Jerome
Davin
error
firstname

Question 15 Multiple Choice (Single Answer)

What is the output of the below JavaScript?

<script>  		
var personObj = {firstname:"Jerome",lastname:"Davin"};  		
alert(personObj.lastname);  	
</script>

Davin
Jerome
error
lastname

← Back to Quizzes