How to Create an Interface Definition in Java
An interface definition specifies one or more methods by signature (method return type, name, and arguments). The interface does not contain implementation logic for the methods with the exception of any methods marked as
default. Therefore, the actual coding of a method can be deferred until a Java program is written to implement an interface and specify method logic for the non-default methods listed in the interface. To create an interface definition in Java, follow these three steps.
- Open your text editor and type in the following Java statements:
The interface defines three methods for displaying a name and optionally a job title. One method is a default method that contains implementation logic. The remaining two methods do not include implementation logic.
- Save your file as CreateAnInterfaceDefinition.java.
- Open a command prompt and navigate to the directory containing your Java program. Then type in the command to compile the source and hit Enter.
The interface is now ready to be implemented by a Java program.