Subclass & Setters

Based off of this Date class

Structure: … SubClass > Constructor > Super > Setter


IncDate is a subclass of the Date class because of the extends keyword.


The obligatory (?) constructor of the IncDate subclass is composed of the newMonth, newDay, newYear variable parameters.


The super keyword passes the constructor’s parameters of the subclass to the superclass. This exists because java isn’t directly able to inherit constructors.


The setter method, also known as the Transformer method, changes the “internal” state of an object. For example, setter methods may change the variable of a object from one value to another.

Also notice that setter methods do not return a value, therefor have the void modifier in the method header.

public class IncDate extends Date {

public IncDate(int newMonth, int newDay, int newYear) {
// Initializes this IncDate with the parameter values
super(newMonth, newDay, newYear);

public void increment() {
// Increments this IncDate to represent the next day, i.e.,
// this = (day after this)
// For example if this = 6/30/2003 then this becomes 7/1/2003
// Increment algorithm goes here



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