Lambda - JavaMasterClass/JavaMasterClass.github.io GitHub Wiki

Functional Interface

• A lambda function implements a Functional Interface
• A functional interface:
  • have only one abstract method.
  • have as many default, static methods.
  • can have methods from object class.
  • @FunctionalInterface may be used on functional Interface.

Define functional interface

@FunctionalInterface
public interface Supplier<T> {
   T get();
}

Implement

Supplier<String> supplier = () -> "Hello World!";

Call

System.out.printf("%s %s", "Output", supplier.get());

• Avoid Auto-boxing, Auto-unboxing