See
Java Tutorials - Using the Keyword super for details and examples.
Note that "if a constructor does not explicitly invoke a superclass constructor, the
Java compiler automatically inserts a call to the no-argument constructor of the superclass." So if the no-argument constructor is what you want, there isn't a need to insert "super()" without arguments.
On the other hand, if you want to invoke a superclass constructor with arguments, then you must explicitly call super(args...) from the subclass constructor.