Interfaces

An interface in Java serves as a contract that defines methods for implementing classes, allowing interactions without exposing implementation details. Unlike abstract classes, interfaces cannot contain instance variables or provide implementation, focusing solely on method signatures. They support multiple inheritance as a class can implement multiple interfaces. Default methods enhance interfaces by enabling method additions without affecting existing implementations. Interfaces also allow the use of marker interfaces, which provide a type reference without methods. Practical examples include the Iterable interface, facilitating iteration for collections like Lists.