Java Interface Quiz

Which keyword is used to implement an interface in Java?

• uses
• implements
• inherits
• extends

What will be the output of this code?

• Compilation error

• Method A

• Runtime error

• No output

What happens if a class implements an interface but does not provide implementations for all of its methods?

• The class can be instantiated without any restrictions.
• The class must be declared abstract.
• The class will automatically implement the missing methods.
• The class will compile without errors.

What is the default access modifier for methods declared in an interface?

• private

• protected
• package-private
• public

Which of the following is true about interfaces in Java?

• Interfaces can contain method signatures and static final variables, but cannot contain method implementations.

• Interfaces can contain method implementations without restrictions.
• Interfaces can only contain private methods.
• Interfaces cannot contain any variables.

What keyword is used to inherit from a class and to implement an interface in Java?

• inherit, derive

• extends, extends

• extends, implements

• implements, extends

Which of the following is true regarding multiple inheritance in Java?

• Java does not allow any form of inheritance.
• Java supports multiple inheritance only through classes.
• Java allows multiple inheritance with classes and interfaces.
• Java does not support multiple inheritance with classes, but it allows multiple inheritance through interfaces.

Which of the following correctly distinguishes a class from an interface in Java?

• Both classes and interfaces can have constructors

• Only interfaces can have constructors

• Only classes can have constructors

• 
  
  Neither classes nor interfaces can have constructors

Why can’t interfaces have constructors in Java?

• Interfaces can have constructors if they extend a class.
• Interfaces cannot have constructors because they cannot be instantiated.
• Constructors in interfaces are used for initialization.
• Interfaces can be instantiated like classes.