1. Description
2. Method Summary
3. Method Details
   1. identity()

Hide sidebar  Show sidebar Type Parameters: T - the type of the operand and result of the operator All Superinterfaces: Function<T,T> Functional Interface: This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

• Method Summary

  Static Methods

  Modifier and Type

  Method

  Description

  static <T> UnaryOperator<T>

  identity()

  Returns a unary operator that always returns its input argument.

  Methods declared in interface Function

  andThen, apply, compose

  Modifier and Type

  Method

  Description

  default <V> Function<T,V>

  andThen(Function<? super T, ? extends V> after)

  Returns a composed function that first applies this function to its input, and then applies the after function to the result.

  T

  apply(T t)

  Applies this function to the given argument.

  default <V> Function<V,T>

  compose(Function<? super V, ? extends T> before)

  Returns a composed function that first applies the before function to its input, and then applies this function to the result.

• Method Details

  • identity

    static <T> UnaryOperator<T> identity()

    Returns a unary operator that always returns its input argument.

    Type Parameters: T - the type of the input and output of the operator Returns: a unary operator that always returns its input argument

Report a bug or suggest an enhancement
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples. Other versions.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries.
Copyright © 1993, 2026, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy.