I am new to functional programming, so far i have understood how to use it, anonymous function etc.
I saw many examples of code where the object needed as parameter in my lambda expression actually doesn't exist in that moment (it isn't instantiated).
For example, is this:
myClass.myMethod(c -> {my overridden code});
the same as this
myClass.myMethod(new String() -> {my overridden code});
considering that c
is not declared in my code and myMethod
correctly implements a functional interface which abstract method requires a String?
EDIT:
I got some problems with this question: JavaFX ComboBox Image With this part of code:
comboBox.setCellFactory(c -> new StatusListCell());
I can't figure out where c is taken from, it's not declared at all, that's why i was wondering if lambda expressions could create new objects automatically.
c
is actually only a placeholder, like a parameter in a method would be (which does not differ from the functioning of the lambda here).
myClass.myMethod(c -> {my overridden code});
is the equivalent of the following
myClass.myMethod(new Consumer<String>(){
@Override
public void accept(String c) {
{my overridden code}
}
}
So the answer to your question is : No. The lambda represents a method, a function but is not an executable piece by itself, it has to be invoked with outside parameters.