I know that in case of Inheritance the subClass constructor should call the superClass constructor explicitly if the default constructor in the superClass is missing

but when chaining to another constructor in the subClass why we don't have to call the superClass Constructor then?
as the code below is not giving a compilation error

SuperClass:

```
public class Top {
    public Top(String n) {
        // TODO Auto-generated constructor stub
    }

```

SubClass:

```
public class sub extends Top {

    public sub(int x){
        super("");
    }
    public sub(String x) {
        this(5);
    }
}

```