first off you question sounds like "how do I do first class functions in java" historically that answer was "make a class with one method, it's shit suck it" things are better now though. But really ...

Along with lambdas, Java SE 8 brought method references to the Java language. This tutorial offers a brief overview of method references in Java, then gets you started using them with Java code ...

Method references are a shorthand way to write lambda expressions that call a single method. Rather than implementing a method in a functional interface, a method reference simply points to an ...