Ben Wharnsby
Quiz by , created more than 1 year ago

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Ben Wharnsby
Created by Ben Wharnsby over 9 years ago
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Java quiz!

Java quiz!

Question 1 of 32

1

Definition: Describes an object in Java. Objects are created from these. Blueprints for a type of object. What am i?

Select one of the following:

  • Primitive Type

  • Class

  • Object

  • Field

Explanation

Question 2 of 32

1

An Object is a ...?

Select one of the following:

  • Dynamic Entity, Created after constructor is invoked; collection of instance variables represent status.

  • Shape, relationship and model.

  • A value stored in associative memory.

  • Blueprint of an class.

Explanation

Question 3 of 32

1

Difference between Primitive and Reference types?

Select one of the following:

  • Primitives are stored as status of objects and Reference types are stored in memory as values.

  • Primitive types are stored in associative memory as a value; Reference types are stored in associative memory as an address of object state.

  • No differences, both stored in associative memory.

  • Both are dynamic entities.

Explanation

Question 4 of 32

1

Difference between CLASS FIELD and INSTANCE VARIABLE?

Select one of the following:

  • Fields are the types of data used in the class and an instance variable is used when a object is created allowing you to call the fields from a class.

  • Fields in class definition specify types of data that consistute to the status of the object. Instance variables are created when the class constructor is invoked; an instance variable is set to each field.

  • Class fields use the static modifier and are the types of data used in a class; instance variables allow you to reference data outside of a class.

  • Class fields must always use the public modifier and instance variables are assigned to each field in the class on invoked.

Explanation

Question 5 of 32

1

A Constructor contains a return type and starts with CAPITAL letters? True or False.

Select one of the following:

  • True
  • False

Explanation

Question 6 of 32

1

A method contains a Return type and by convention starts with lower case letters, addMoney(). True or False.

Select one of the following:

  • True
  • False

Explanation

Question 7 of 32

1

Which of these represents a Constant Identifier?

Select one of the following:

  • final boolean public normal_working_week = 37.5;

  • final boolean public NORMAL_WORKING_WEEK = 37.5;

  • final DOUBLE NORMAL_WORKING_WEEK = 37.5;

  • DOUBLE NORMAL_WORKING_WEEK = 37.5;

Explanation

Question 8 of 32

1

What is a class variable?

Select one of the following:

  • private static bookCount = 0;
    public Book {
    bookCount++;
    }

  • private final bookCount = 0;
    public Book {
    bookCount++;
    }

  • static private bookCount = 0;
    public Book {
    bookCount++;
    }

  • private int bookCount = 0;
    public Book {
    bookCount++;
    }

Explanation

Question 9 of 32

1

What is the sequence to create a count for True and False values?

Select one of the following:

  • Create a fixed sized array.
    Initialise 'n' elements with the int 0.
    For loop to iterate through array, checking if the value is True or False.
    Increment index 0, by 1 if true; index 1 by 1, if false.
    Return new array, [1, 2];

  • Initialise 'n' elements with the int 0.
    Create a fixed sized array.
    Increment index 0, by 1 if true; index 1 by 1, if false.
    For loop to iterate through array, checking if the value is True or False.
    Return new array, [1, 2];

  • Initialise 'n' elements with the int 0.
    Create a fixed sized array.
    Create a arraylist of type boolean.
    Increment index 0, by 1 if true; index 1 by 1, if false.
    For loop to iterate through array, checking if the value is True or False.
    Return new array, [1, 2];

  • Initialise 'n' elements with the int 0.
    Create a fixed sized array.
    Increment index 0, by 1 if true; index 1 by 1, if false.
    For loop to iterate through array, checking if the value is True or False.
    Return new array;

Explanation

Question 10 of 32

1

Difference between an Array and an ArrayList?

Select one of the following:

  • Array --> Fixed size, element can of only one type, but this type can be primitive/reference.
    ArrayList --> Variable size, elements can be reference types.

  • Array --> Variable size, element can be any type, but this type can be primitive/reference.
    ArrayList --> Variable size, elements can be reference types.

  • Array --> Variable size, element can be any type, but this type can be primitive/reference.
    ArrayList --> Fixed size, elements can be reference/primitive types.

  • Array --> Fixed size, element can of only one type, but this type can be primitive/reference.
    ArrayList --> Variable size, elements can be reference/primitive types.

Explanation

Question 11 of 32

1

ArrayList<BankAccount> currentAccounts = new ArrayList<BankAccount>();
Is this Correct?

Select one of the following:

  • True
  • False

Explanation

Question 12 of 32

1

Accessor methods --> Changes state of object by updating a value of instance variables.
Mutator methods --> Return information about the state of 'this' object. Doesn't change the value of a field.

Select one of the following:

  • True
  • False

Explanation

Question 13 of 32

1

public boolean sendToService() {
return lastService + serviceInterval <= mileage;
}

Select one of the following:

  • True
  • False

Explanation

Question 14 of 32

1

What is recursion?

Select one of the following:

  • Process of a method calling another method.

  • Process of a method calling itself.

  • Process of a class calling another method.

  • Process of a class calling itself.

Explanation

Question 15 of 32

1

What are the 2 rules of Recursion?

Select one of the following:

  • Must have at least 2 base classes + must ensure recursive calls eventually reach the base classes.

  • Must have at least 1 base class + must ensure recursive calls eventually reach the base class.

  • Must have at least 1 base class + must ensure recursive call at least one field in the class.

  • Must have at least 1 base class + must ensure recursive calls contain more than one argument.

Explanation

Question 16 of 32

1

Tail Recursion --> Where the return is the last operation that happens in recursion. True? False?

Select one of the following:

  • True
  • False

Explanation

Question 17 of 32

1

Recursive is better than Iterative, true or false?

Select one of the following:

  • True
  • False

Explanation

Question 18 of 32

1

What is an algorithm?

Select one of the following:

  • A method in Java which is used to count the number of elements in an arrayList.

  • Step by step process to solve a problem. Step by step instructions which termine and uses pseudo code.

  • Step by step process to solve a problem. Step by step instructions which termine on a method and uses real code and Java statements.

  • Step by step process to solve a linear search. Step by step instructions which termine on a method and uses real code, english and expressions.

Explanation

Question 19 of 32

1

Worst-Case Complexity --> Maximum amount of computation used on an instance of a certain size. True or false?

Select one of the following:

  • True
  • False

Explanation

Question 20 of 32

1

SelectionSort Algorithm:

a = [a1, a2, ..., an]

k = 1
for i from 1 to (n - 1) do:
find item, next that should be in position 'i' in the sorted array.
swap items a, and next.
next = an (array reference);
indexOfNext = i;

for j from i+1 to n do:
if aj < next then:
next = aj
indexOfNext = j
endif

Is the complexity N^2?

Select one of the following:

  • True
  • False

Explanation

Question 21 of 32

1

Declare int indexOfNext and Comparable next;
For loop to iterate through array, but last element.
In for loop, assign next variable the current element and indexOfNext 'i'.
Still in for loop, do another for loop to iterate through all elements after current index, compare elements using compareTo() and assign next to a[j] and indexOfNext to 'j'; if next element is less than current element.
After 'j' for loop, a[indexOfNext] = a[i]; && a[i] = next; (Switch places).
Continue to loop!

Select one of the following:

  • True
  • False

Explanation

Question 22 of 32

1

Is this a correct statement?
Sorting.selectionSort(facebookFriends);

Select one of the following:

  • True
  • False

Explanation

Question 23 of 32

1

What is inheritance?

Select one of the following:

  • Where a class implements another class or method. Features are inherited too.

  • Where the subclass can inherit features and methods from another base class.

  • Where the base class can inherit features and methods from another base class.

  • Where the subclass can inherit only methods from another base class.

Explanation

Question 24 of 32

1

Public class House extends Building {
private int numBedrooms;
public void setNumBedrooms(int a) {
numBedrooms = a;
}
}

Is this Inheritance?

Select one of the following:

  • True
  • False

Explanation

Question 25 of 32

1

What is the relationship between Building and House?

Select one of the following:

  • Association

  • Encapulsation

  • Inheritance

  • Dynamic Binding

Explanation

Question 26 of 32

1

If we create a class, Street; what is it's relation to House?

Select one of the following:

  • Association.

  • Aggregation.

  • Encapulsation

  • Inheritance.

Explanation

Question 27 of 32

1

public class Street {
...
}

Select one of the following:

  • House[] houses;
    private String name;

    public Street(int b, String n) {
    name = n;
    houses = new House(b);
    }

  • ArrayList<House> houses;
    private String name;

    public Street(int b, String n) {
    name = n;
    houses = new House(b);
    }

  • ArrayList<House> houses;
    private String name;

    public Street(int b, String n) {
    name = n;
    houses = new House(b);
    name = b;
    }

  • House[] houses;
    private Int name;

    public Street(int b, String n) {
    name = n;
    houses = new House(b);
    }

Explanation

Question 28 of 32

1

Method Overriding?
Subclass changes it's behaviour of the baseclass, keeping the same method signature.

Select one of the following:

  • True
  • False

Explanation

Question 29 of 32

1

Polymorphism
A variable to hold just one reference to different types of classes.

Select one of the following:

  • True
  • False

Explanation

Question 30 of 32

1

Dynamic Binding

Operation to apply polymorphic variable is determined at runtime.
Depending on which class is currently assigned to a value (Account s), depends on which method is called.

Select one of the following:

  • True
  • False

Explanation

Question 31 of 32

1

What is an interface?

Select one of the following:

  • Collection of methods and objects.

  • Collection of abstract methods.

  • Collection of methods.

  • Collection of fields.

Explanation

Question 32 of 32

1

Does a class that implement an interface have to implement all methods?

Select one of the following:

  • True
  • False

Explanation

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