Trail: Learning the Java Language
Lesson: Interfaces and Inheritance
Section: Interfaces
Summary of Interfaces
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Summary of Interfaces

An interface defines a protocol of communication between two objects.

An interface declaration contains signatures, but no implementations, for a set of methods, and might also contain constant definitions.

A class that implements an interface must implement all the methods declared in the interface.

An interface name can be used anywhere a type can be used.

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