Introduction to the difference between java abstract classes and interfaces

The difference between abstract classes and interfaces

Abstract Class

The class containing abstract methods is an abstract class, and the statement declared: abstract class
Must be public protected

interface

Abstraction of behavior, statement: interface
Modifier for abstract method: public abstract
Modifier for member variables: public static final

Syntax Level

1. Abstract classes can contain implementation details of member methods, while only abstract methods can exist in the interface - public abstract
2. Member variables in abstract classes can be of various types, and member variables in interfaces can only be public static final
3. Abstract classes can contain static methods and static code blocks, but cannot contain
4. A class can only inherit one abstract class and can implement multiple interfaces
5. The access modifier is different: the modifier of the abstract class method is public/protected; the modifier of the method in the interface must be public

Design level

Abstract classes are abstractions of things and abstractions of classes; interfaces are abstractions of behaviors, describing a behavioral norm

Abstract classes are abstract descriptions of the entire class, including attributes and behaviors; interfaces can only abstract the behavior of the class.

Attached a picture:

Thank you for reading, I hope it can help you. Thank you for your support for this site!