How do you define a class interface?

An interface is declared by using the interface keyword . It provides total abstraction; means all the methods in an interface are declared with the empty body, and all the fields are public, static and final by default. A class that implements an interface must implement all the methods declared in the interface.

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What is Java implementation?

Implementations are the data objects used to store collections, which implement the interfaces described in the Interfaces lesson . The Java Collections Framework provides several general-purpose implementations of the core interfaces: For the Set interface, HashSet is the most commonly used implementation.

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