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Function interface

Function<T,R> is a Functional Interface within the Java framework, specifically categorized as a unary function from T to R^[600-developer__java__java8__java8-lambda.md]. It is designed to represent a method that accepts a single argument and produces a result.^[600-developer__java__java8__java8-lambda.md]

Type Parameters

The interface is defined by two generic type parameters:

  • T: the type of the input (parameter) provided to the function.^[600-developer__java__java8__java8-lambda.md]
  • R: the type of the result (return value) produced by the function.^[600-developer__java__java8-lambda.md]

Usage

To invoke the function encapsulated by a Function object, the apply method is used^[600-developer__java__java8__java8-lambda.md]. This allows the logic defined within the interface implementation to be executed with the provided argument^[600-developer__java__java8__java8-lambda.md].

  • [[Consumer]]: A unary function from T to void.
  • [[Predicate]]: A unary function from T to boolean.
  • [[Supplier]]: A function with no arguments that returns R.
  • [[Lambda]]

Sources

^[600-developer__java__java8__java8-lambda.md]