Java – self executing anonymous functions via Lambdas

In JavaScript, there is a common pattern of creating an anonymous function and calling it immediately (usually called self executing anonymous function or immediately invoked function expression)

Using java 8 Lambdas, is there a standard way to replicate this behavior? Things like (() – > dosomething ()) ()

This question basically asks the same question, but for Java 7 I explicitly look for constructs that use Lambdas

Solution

Is not an undeclared type Because Java is a statically typed language and functions are not first class citizens, the compiler needs to know the type of lambda A function cannot just float, it always needs to be associated with a class or an instance of a class

Runnable r = () -> {
    System.out.println("Hello World!");
};
r.run();

However: you can convert lambda to runnable type and give the compiler a hint about the @ functionalinterface type you are implementing:

((Runnable)() -> {
    System.out.println("Hello World!");
}).run();

Or there are no parentheses, which makes it a single line:

((Runnable)() -> System.out.println("Hello World!")).run();

I think it's as close as you'll get!