Ben Wharnsby
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Ben Wharnsby
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Java quiz!

Frage 1 von 32

1

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

Wähle eine der folgenden:

  • Primitive Type

  • Class

  • Object

  • Field

Erklärung

Frage 2 von 32

1

An Object is a ...?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 3 von 32

1

Difference between Primitive and Reference types?

Wähle eine der folgenden:

  • 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.

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Frage 4 von 32

1

Difference between CLASS FIELD and INSTANCE VARIABLE?

Wähle eine der folgenden:

  • 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.

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Frage 5 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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Frage 6 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 7 von 32

1

Which of these represents a Constant Identifier?

Wähle eine der folgenden:

  • 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;

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Frage 8 von 32

1

What is a class variable?

Wähle eine der folgenden:

  • 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++;
    }

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Frage 9 von 32

1

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

Wähle eine der folgenden:

  • 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;

Erklärung

Frage 10 von 32

1

Difference between an Array and an ArrayList?

Wähle eine der folgenden:

  • 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.

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Frage 11 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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Frage 12 von 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.

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 13 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 14 von 32

1

What is recursion?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 15 von 32

1

What are the 2 rules of Recursion?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 16 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 17 von 32

1

Recursive is better than Iterative, true or false?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 18 von 32

1

What is an algorithm?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 19 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 20 von 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?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 21 von 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!

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 22 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 23 von 32

1

What is inheritance?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 24 von 32

1

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

Is this Inheritance?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 25 von 32

1

What is the relationship between Building and House?

Wähle eine der folgenden:

  • Association

  • Encapulsation

  • Inheritance

  • Dynamic Binding

Erklärung

Frage 26 von 32

1

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

Wähle eine der folgenden:

  • Association.

  • Aggregation.

  • Encapulsation

  • Inheritance.

Erklärung

Frage 27 von 32

1

public class Street {
...
}

Wähle eine der folgenden:

  • 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);
    }

Erklärung

Frage 28 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 29 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 30 von 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.

Wähle eins der folgenden:

  • WAHR
  • FALSCH

Erklärung

Frage 31 von 32

1

What is an interface?

Wähle eine der folgenden:

  • Collection of methods and objects.

  • Collection of abstract methods.

  • Collection of methods.

  • Collection of fields.

Erklärung

Frage 32 von 32

1

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

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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