Difference between interface and abstract

Question

Accepted Answer

Interface defines only method signatures while abstract class can have both method signatures and implementations.

An interface can be implemented by multiple classes while an abstract class can only be extended by one class.
An abstract class can have constructors while an interface cannot.
An abstract class can have instance variables while an interface cannot.
An abstract class can have non-abstract methods while an interface can only have abstract methods.
An abstract class can be used to provide a default implementation for some methods while an interface cannot.
Example of interface: Runnable interface in Java.
Example of abstract class: Animal class in a zoo simulation program.

Accepted Answer

1.

Interface can have only abstract methods. Since Java 8, it can have default and static methods also.

2.

Interface supports multiple inheritance.

3.Interface has only static and final variables.

1.Abstract class can have abstract and non-abstract methods

2.Abstract class doesn't support multiple inheritance.

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