Java8 06 BuiltIn Functional Interface
Java 8 introduced Lambda expressions and method reference syntax. Lambda expressions are allowed only for Functional Interfaces. Lambda expressions are quite easy to write and reduce number of LOC dramatically. Since Lambda expression are quite useful, Java 8 added few built-in functional interfaces under java.util.function so that programmers don’t need to write them again and use them through lambda expression. It’s useful to know about these built-in functional interfaces as It will definitely accelerate your java coding. In case you forgot what is Functional Interface: