Constructor method's running in the background

Do these course’s statements mean that constructor method is actually starting to run IN THE BACKGROUND and NOT SEEN TO US?

This constructor method is used whenever we instantiate an object with the new keyword:

If no constructor is defined in a class, one is automatically created for us. It takes no parameters, so it’s called a parameterless constructor .

 // Constructor is called hereForest f = new Forest(400);