I am looking for a way to pass a method by reference. I understand that Java does not pass methods as parameters, however, I would like to get an alternative. 

I've been told interfaces are the alternative to passing methods as parameters but I don't understand how an interface can act as a method by reference. If I understand correctly an interface is simply an abstract set of methods that are not defined. I don't want to send an interface that needs to be defined every time because several different methods could call the same method with the same parameters.

What I would like to accomplish is something similar to this:

```
public void setAllComponents(Component[] myComponentArray, Method myMethod) {
    for (Component leaf : myComponentArray) {
        if (leaf instanceof Container) { //recursive call if Container
            Container node = (Container) leaf;
            setAllComponents(node.getComponents(), myMethod);
        } //end if node
        myMethod(leaf);
    } //end looping through components
}

```

invoked such as:

```
setAllComponents(this.getComponents(), changeColor());
setAllComponents(this.getComponents(), changeSize());

```