UnaryOperator
is a functional interface that represents a single-operand operation which yields a result of the same type as the operand.
The interface extends the Function
interface so the methods of the Function
interface can be used on the implementation of the UnaryOperator
interface. The interface overrides the identity()
method of the Function
interface.
The UnaryOperator
interface is defined in the java.util.function
package. To import the UnaryOperator
interface, use the following import statement:
import java.util.function.UnaryOperator;
identity()
method?The identity()
method is a static method used to return a unaryOperator
that always returns its input argument.
static <T> UnaryOperator<T> identity()
The method has no parameters.
This method returns the input argument.
import java.util.function.UnaryOperator;public class Main{public static void main(String[] args) {// Identity unary operator that accepts one inputUnaryOperator<Integer> unaryOperator = UnaryOperator.identity();// argumentint arg = 3;System.out.printf("UnaryOperator.identity(%s) = %s", arg, unaryOperator.apply(3));}}
unaryOperator
that accepts one input of integer type.unaryOperator
using the apply()
method on the integer value defined in line 11 and print the result.