OOP mentore week 9

• Natuurkunde
• Middelbare school

Welcome!

Static binding happens at runtime

1. True
2. False

Java allows multiple inherintance

1. True
2. False

Using Optional<> avoid all NullPointerExceptions

1. True
2. False

You can add a char to a ArrayList<Characters>
(without getting exceptions)

1. True
2. False

Writing good tests guarantees a program will not crash

1. True
2. False

Which interpretation of the keyword abstract is false?

1. Making a class abstract means that all of its methods should be abstract
2. Making a class abstract means that it cannot be instantiated
3. A concrete subclass must implement abstract methods in its parent

Which is not a valid way to start a new thread?

1. Extend the class Thread and call .start() on an instance of this class
2. Create a Thread with a lambda as argument and call .start()
3. Implement the interface Runnable and call .run()

Which of the following cannot be caught in a catch block?

1. StackOverflowError
2. IOException
3. ArrayIndexOutOf BoundsException

When attempting to cast between incompatible types...

1. The program will not compile
2. The program will raise an exception on runtime
3. The incompatible fields will be filled with null

Which statement about BufferedReader and Scanner is false?

1. Scanner can be used to read from an InputStream
2. A BufferedReader is a reader that takes a reader as an argument
3. BufferedReader can only read a single character at a time

Which is true?

1. This method does not compile
2. This method will raise an ArrayIndexOutOf BoundsExcpetion
3. This method will raise a NullPointException
4. This method will work without problema

1. CoffeeMachine extends Machine and Grinder extends CoffeeMachine
2. CoffeeMachine extends Machine and CoffeeMachine implements Ginder as interface
3. CoffeMachine extends Machine and Grinder is attribute of CoffeMachine by use of composition
4. CoffeeMachine extends Machine but not relation between CoffeeMachine and Grinder (they don't share properties)

Which is
true?

1. The test does not compile
2. The test passes
3. The test fails
4. The test leads to a runtime exception

What is
the outcome?

1. The program does not compile
2. 18
3. 36
4. 54

Which
is true?

1. The program does not compile
2. A runtime exception occurs
3. "A pair of animals" is printed
4. "A pair of coatis" is printed