In Java, Function T, R is part of the java.util.function package, which provides a functional interface for operations. It represents a function that accepts one argument of type T and produces a result of type R. This is particularly useful in functional programming paradigms, especially with stream operations, allowing for concise and expressive code. It enhances readability and maintainability by abstracting complex operations into simpler, functional chunks. Function T, R is often used with lambda expressions for inline implementations.


This code demonstrates the use of Function T, R by defining a function that squares an integer. It applies this function to a list of integers using a stream, transforming each element and collecting the results into a new list. The simplicity and expressiveness of this approach highlight the power of functional interfaces in Java.