Prior versions of Java also lack predefined functional interfaces and first-class functions such as filter and map. Java 8 reduces verbosity largely by introducing lambdas and method references to ...

How to use Java’s Function interface. For this Java Function interface example, we will provide a single method named “apply” that takes an Integer as an argument, squares it and returns the result as ...

The map function is not. ... In Java, we could create a functional interface to share that operation: static class LastNameComparator implements java.util.Comparator ...

In Java, there are many, many places in which a piece of code needs a single method implementation. And there are many interfaces in the Java API where only a single method needs to be implemented.