Arrays QuizJ8 Home « Objects & Classes Quiz

The questions in this Java quiz are on the topics covered in the java - Objects & Classes section of the site. The table below lists the lesson used for each quiz, a description of the lesson content and the quiz number and questions associated with that lesson.

Lesson Summary

Click on a lesson in the table to go to that lesson for a refresher on the topics for that quiz.

Click on a quiz in the table to go straight to the quiz for a particular lesson.

Objects & Classes Lessons Description Quiz Info.
Lesson 1 - ArraysIn this lesson we look at arrays and how to use them in Java.This quiz.
8 questions
Lesson 2 - Array Examples & ExceptionsIn this lesson we look at some arrays examples and exceptions.Quiz2
8 questions
Lesson 3 - Class Structure & SyntaxFor this lesson we looked at class structure and syntax within our Java programs.Quiz3
8 questions
Lesson 4 - Reference VariablesThis lesson is about reference variables and how to use them within our Java programs.Quiz4
7 questions
Lesson 5 - Methods - BasicsWe have used methods throughout the lessons so its now time for a thorough investigation of what we can do with these members by starting with the basics.Quiz5
7 questions
Lesson 6 - Methods - Passing ValuesIn our second lesson on Java methods we investigate the concept of pass-by-value and what this means when we pass values to our methods.Quiz6
6 questions
Lesson 7 - Methods - Overloading & VarargsIn our final lesson on Java methods we look at method overloading and variable arguments.Quiz7
7 questions
Lesson 8 - Instance Variables & ScopeThis lesson is about instance variables, how to use them and their scope.Quiz8
7 questions
Lesson 9 - Final Instance VariablesThis lesson is about final instance variables, how we use them and the rules associated with them.Quiz9
7 questions
Lesson 10 - Constructor BasicsIn this lesson we learn the basics about constructors and how we use them to instantiate objects of our classes.Quiz10
7 questions
Lesson 11 - Overloaded Constructors and thisIn this lesson we learn constructor overloading and how to use the this keyword.Quiz11
9 questions
Lesson 12 - Static OverviewIn the first of three lessons on statics we investigate what the static keyword means and how to use static variables.Quiz12
7 questions
Lesson 13 - Static MethodsIn this lesson we look at static methods and how to use them within our Java classes.Quiz13
6 questions
Lesson 14 - Java ConstantsIn this lesson we investigate Java constants and how to use static initializer blocks.Quiz14
7 questions
Lesson 15 - Basic EnumerationsIn the first of two lessons on enumerations which were introduced in Java5, we look at the basics.Quiz15
8 questions
Lesson 16 - Advanced EnumerationsIn our final lesson of this section we look at some advanced uses of enumerations.Quiz16
6 questions

Java Objects & Classes Quiz 1

The quiz below tests your knowledge of the material learnt in Objects & Classes - Lesson 1 - Arrays.

Question 1 : What is the second step of array creation?
- Array allocation is the second step of creating an array.
Question 2 : We can look at an element of an array after array declaration?
- We can only look at an element within an array after allocation. After declaration no size has been allocated.
Question 3 : What will be output from this code snippet?

String strArray[] = {"one", "aa", "c", "rt", "je"};
System.out.println(strArray[1]);
- The output will be <code>aa</code>. Arrays are zero-index based
Question 4 : What will be output from this code snippet?

String strArray3[] = new String[3]{"one", "rt", "je"};
System.out.println(strArray3[1]);
- The code doesn't compile. When using a single statement to create an array, no size should be specified.
Question 5 : Which of the following statements will compile?

int intArray1[][]; // A
int[][] intArray2; // B
int[] intArray3[]; // C
- All the statements will compile as the square brackets can follow the type, the array name or be split between the two for multi dimensional arrays.
Question 6 : What will be output from this code snippet?

String[] strArray1;; // Array declaration
strArray1 = new String[1]; // Array allocation
System.out.println(strArray1[0]);
- The output will be <code>null</code> as space has been allocated so array is initialized to default.
Question 7 : We can have a maximum of two dimensions for arrays?
- There is actually no limit to the amount of dimensions an array can have although in practical terms arrays are rarely more than three dimensions.
Question 8 : What will be result when this code snippet is run?

int intArray1[]; // 1
intArray1 = int[2]; // 2
intArray1[0] = 22; // 3
intArray1[1] = 44; // 4
System.out.println(intArray1[0]); // 5
- Doesn't compile. The <code>new</code> keyword is mandatory for multiple statement array creation.<br>The code would compile and output <code>22</code> if line 2 changed to <code>intArray1 = new int[2];</code>.
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What's Next?

The next quiz on Java Objects & Classes is array exceptions and examples.