IFunctionalInterface Interface

Definition

[Android.Runtime.Register("java/lang/FunctionalInterface", "", "Java.Lang.IFunctionalInterfaceInvoker", ApiSince=24)]
public interface IFunctionalInterface : IDisposable, Java.Interop.IJavaPeerable, Java.Lang.Annotation.IAnnotation

[<Android.Runtime.Register("java/lang/FunctionalInterface", "", "Java.Lang.IFunctionalInterfaceInvoker", ApiSince=24)>]
type IFunctionalInterface = interface
    interface IAnnotation
    interface IJavaObject
    interface IDisposable
    interface IJavaPeerable

Attributes

RegisterAttribute

Implements

IJavaObject IJavaPeerable IAnnotation IDisposable

Remarks

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.

Conceptually, a functional interface has exactly one abstract method. Since java.lang.reflect.Method#isDefault() default methods have an implementation, they are not abstract. If an interface declares an abstract method overriding one of the public methods of java.lang.Object, that also does <em>not</em> count toward the interface's abstract method count since any implementation of the interface will have an implementation from java.lang.Object or elsewhere.

Note that instances of functional interfaces can be created with lambda expressions, method references, or constructor references.

If a type is annotated with this annotation type, compilers are required to generate an error message unless:

<ul> <li> The type is an interface type and not an annotation type, enum, or class. <li> The annotated type satisfies the requirements of a functional interface. </ul>

However, the compiler will treat any interface meeting the definition of a functional interface as a functional interface regardless of whether or not a FunctionalInterface annotation is present on the interface declaration.

Added in 1.8.

Java documentation for java.lang.FunctionalInterface.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Properties

Methods

Extension Methods

Applies to