Clases abstractas e iinterfaces

1. 1. What is the purpose of using an abstract class?

• • To enforce some rules on subclasses

• • To hide the implementation details from subclasses

• • All of the above

• • To provide a common interface for subclasses

  
  

2. 2. What is the difference between an abstract method and a non-abstract method in an abstract class?

• • An abstract method has no body and must be overridden by subclasses, while a non-abstract method has a body and can be inherited by subclasses.

• • An abstract method has a body and can be inherited by subclasses, while a non-abstract method has no body and must be overridden by subclasses.

• • An abstract method has no body and must be declared with the final keyword, while a non-abstract method has a body and can be declared with any keyword.

• • An abstract method has no body and must be declared with the static keyword, while a non-abstract method has a body and can be declared with any keyword.

3. 3. What is the syntax for declaring an abstract class in Java?

• • class ClassName extends AnotherClass implements InterfaceName

• • abstract class ClassName extends AnotherClass implements InterfaceName

• • abstract class ClassName extends AnotherClass

• class ClassName extends AnotherClass

  
  

4. 4. What is the purpose of using an interface in Java?

• • To provide a common interface for classes that share some functionality

• • To hide the implementation details from classes that use them

• • To enforce some rules on classes that implement them

• • All of the above

5. 5. What is the difference between an interface and an abstract class in Java?

• An interface can only have public methods, while an abstract class can have any access modifier for its methods

• All of the above

• An interface can only have abstract methods, while an abstract class can have both abstract and non-abstract methods

• An interface can only extend one other interface, while an abstract class can extend multiple classes or interfaces

6. 6. What is the syntax for declaring an interface in Java?

• interface InterfaceName { ... }

• abstract class InterfaceName { ... }

• class InterfaceName implements InterfaceName { ... }

• interface InterfaceName extends AnotherInterface { ... }