java this(null)
public Settings() {
this(null); //this is calling the next constructor
}
public Settings(Object o) {
// this one
}
This is often used to pass default values so you can decide to use one constructor or another..
public Person() {
this("Name");
}
public Person(String name) {
this(name,20)
}
public Person(String name, int age) {
//...
}
It means you are calling an overloaded constructor which takes an Object
of some sort but you do not pass an object, but a plain null
.
It's a constructor that is calling another constructor in the same class.
You presumably have something like this:
public class Settings {
public Settings() {
this(null); // <-- This is calling the constructor below
}
public Settings(object someValue) {
}
}
Often this pattern is used so that you can offer a constructor with fewer parameters (for ease of use by the callers) but still keep the logic contained in one place (the constructor being called).