함수형 인터페이스 정리해두기

@FunctionalInterface
public interface Runnable {
    public abstract void run();
}

```java
@FunctionalInterface
public interface Consumer<T> {
    void accept(T t)
}	

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

@FunctionalInterface
public interface Function<T, R>	{
    R apply(T t)
}

@FunctionalInterface
public interface Predicate<T> {	
    boolean test(T t)
}