What is the purpose of DoubleConsumer functional interface

In Java, the DoubleConsumer functional interface is part of the java.util.function package and is designed to represent an operation that takes a single double parameter and returns no result (void). It belongs to the family of functional interfaces introduced in Java 8 to support lambda expressions and functional programming idioms

The DoubleConsumer interface has a single abstract method named accept(double value), which defines the operation to be performed with the given double argument. This interface is particularly useful when you need to specify an operation that consumes a double value, such as in the context of streaming or processing numerical data.

Here's the signature of the DoubleConsumer interface:

        
            @FunctionalInterface
            public interface DoubleConsumer {
                void accept(double value);
                
                // Other default and static methods (if any)...
            }            
        
    

Here's a simple example using DoubleConsumer with a lambda expression:

        
            import java.util.function.DoubleConsumer;

            public class DoubleConsumerExample {
                public static void main(String[] args) {
                    // Using a DoubleConsumer to print the square of a given double value
                    DoubleConsumer squarePrinter = value -> System.out.println(value * value);
            
                    // Applying the consumer
                    squarePrinter.accept(5.0); // Prints: 25.0
                }
            }            
        
    

In this example, the DoubleConsumer is used to define a simple operation (squaring the input) and then applied to a specific double value. Functional interfaces like DoubleConsumer are particularly handy when working with streams, where you can use them as arguments for methods like forEach, map, and others in the java.util.stream package.

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