Podcast
Questions and Answers
What is the default access modifier for interface fields in Java?
What is the default access modifier for interface fields in Java?
- protected
- private
- public (correct)
- static
Which keyword is used to implement an interface in Java?
Which keyword is used to implement an interface in Java?
- use
- inherit
- implements (correct)
- extend
What is a benefit of default methods in Java interfaces?
What is a benefit of default methods in Java interfaces?
- They can be declared via the abstract keyword
- Implementing classes may or may not override them (correct)
- They are implicitly private
- They cannot have a body
Which method is added to the Vehicle interface in the updated version?
Which method is added to the Vehicle interface in the updated version?
Which access modifiers are not allowed for fields in a Java interface?
Which access modifiers are not allowed for fields in a Java interface?
What is the main purpose of an interface in Java?
What is the main purpose of an interface in Java?
Can an interface have concrete (non-abstract) methods?
Can an interface have concrete (non-abstract) methods?
How many interfaces can a class implement in Java?
How many interfaces can a class implement in Java?
What is the main difference between an interface and an abstract class in Java?
What is the main difference between an interface and an abstract class in Java?
If a class implements an interface in Java, what is the requirement?
If a class implements an interface in Java, what is the requirement?
Study Notes
Interface Fields in Java
- The default access modifier for interface fields in Java is
public static final
. - The
implements
keyword is used to implement an interface in Java.
Benefits of Default Methods
- A benefit of default methods in Java interfaces is that they allow developers to add new functionality to interfaces without breaking existing implementations.
Updating Interfaces
- The
printDetails
method is added to theVehicle
interface in the updated version.
Interface Field Access Modifiers
- The
private
andprotected
access modifiers are not allowed for fields in a Java interface.
Purpose of Interfaces
- The main purpose of an interface in Java is to define a contract that must be implemented by any class that implements it.
Interface Methods
- An interface can have concrete (non-abstract) methods, known as default methods, which provide a default implementation that can be overridden by implementing classes.
Implementing Multiple Interfaces
- A class can implement multiple interfaces in Java.
Interfaces vs Abstract Classes
- The main difference between an interface and an abstract class in Java is that an interface cannot have instance variables, while an abstract class can.
Implementing Interfaces
- If a class implements an interface in Java, it is required to provide an implementation for all the abstract methods declared in the interface.
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Description
Learn the concepts of interfaces in Object Oriented Programming (OOP) including how to implement and define interfaces, interface data members, default methods, usages of interfaces like Comparable and Comparator, and the differences between interfaces and abstract classes.