When writing Java code for the sublcass of a class, the first line of the constructor must be the call to

super $().$ Please explain which of the solid principles mandates this. $(2$ marks$).$

Now consider this code:

public class IntSet $\{$

private Vector elements;

public IntSet$()\{$

element $=$ new Vector$()$;

bs

$\}$

public class MaxIntSet extends IntSet$\{$

public MaxIntSet $()\{$

$//$ no code written here

hs

$\}$

Is the principle identified in previous part is still broken? Explain why. $(2$ marks$)$