Nov 20, 2025 · @FunctionalInterface annotation ensures that an interface cannot have more than one abstract method. If multiple abstract methods are present, the compiler throws an …

An informative annotation type used to indicate that an interface type declaration is intended to be a functional interface as defined by the Java Language Specification.

Except if you don't have any concrete implementation of this interface in your compilation unit. You might write a library, defining an interface, but not implementing it yourself. And again, it …

Mar 27, 2025 · It’s recommended that all functional interfaces have an informative @FunctionalInterface annotation. This clearly communicates the purpose of the interface, and …

Mar 17, 2025 · Java provides the @FunctionalInterface annotation to ensure an interface meets the functional interface criteria. Although not mandatory, it’s a good practice to use it for clarity.

Aug 12, 2025 · Java 8 brought a wave of functional programming features to the language—at the heart of this evolution lies the @FunctionalInterface annotation. It enforces and documents a …

In this quick article, we will discuss the usage of Java 8 introduced @FunctionalInterface interface. The @FunctionalInterface annotation indicates that an interface is a functional …

By functionality, any interface having a single abstract method is a functional interface. Java provides a @FunctionalInterface annotation to mark an interface as a functional interface so …

This will be followed by understanding the new @FunctionalInterface annotation introduced in Java 8 and see an example explaining the definition of a custom functional interface.

Nov 12, 2025 · Java 8 introduced the @FunctionalInterface annotation, which is used to mark an interface as a functional interface. Although this annotation is optional, it helps in preventing …