Java Interface Implementation: Using the 'implements' Keyword to Enable Interface Capabilities in Classes

A Java interface is a special abstract type defined using the `interface` keyword. It contains abstract methods (declared without implementation) and cannot be instantiated. It must be implemented by a class or inherited by another interface. The `implements` keyword is used by classes to implement an interface; the class must fulfill all the abstract method commitments specified in the interface, otherwise, it must be declared as an abstract class. There are three steps to implementing an interface: first, define an interface with abstract methods; second, declare the class to implement the interface using the `implements` keyword; third, write concrete implementations for each abstract method. Java supports a class implementing multiple interfaces (separated by commas). The implementing class must ensure that the method signatures (name, parameters, return type) are completely consistent with the interface, and it must implement all abstract methods, otherwise, an error will occur. The `implements` keyword is a core tool that endows a class with interface capabilities. By standardizing definitions and concrete implementations, it enhances code consistency and extensibility. An interface defines "what to do," while `implements` clarifies "how to do it," enabling the class to possess the capabilities stipulated by the interface.