DoublePredicate Interface in Java 8 with code examples

In this blog post, I will be explaining how the Java 8 functional interface DoublePredicate works. To know more about functional interfaces, you can refer this blog post.

The DoublePredicate  interface provides a method called test. This method accepts a parameter of Double data type and returns a boolean. The DoublePredicate interface is a specialization of the Predicate interface. While the Predicate interface accepts any data type, the DoublePredicate  interface accepts a Double value. To see an example of the Predicate interface, refer to this blog post.

DoublePredicate Example

Consider the following code snippet:

public class DoublePredicateDemo {

public static void main(String args[]){
DoublePredicate greaterThan1 = (input) -> input > 1;
System.out.println("0.75 is greater than 0 = "+greaterThan1.test(0.75));
System.out.println("1.12 is greater than 0 = "+greaterThan1.test(1.25));
}

}

Here, the DoublePredicate.Test method checks if the input number is greater than 1. So when the above code is executed, it will print the following output:

0.75 is greater than 0 = false 
1.12 is greater than 0 = true

You can get the source code for this example along with other code for other Java 8 examples at the Github repository here.