Constructors and 'this'

A constructor is a special type of method in a class that is invoked when a new object is created. Its primary purpose is to initialize the state of the object, i.e., to set the initial values for its instance variables. A constructor has the same name as the class and does not have a return type, not even `void`. If you do not explicitly define a constructor in your class, Java provides a default, no-argument constructor for you. However, it's very common to define your own constructors to ensure that objects are created in a valid state. You can have multiple constructors in a class, each with a different set of parameters. This is known as constructor overloading. For instance, a `Person` class might have one constructor that only takes a `name` and another that takes both a `name` and an `age`. Within a constructor (or any instance method), the `this` keyword is a reference to the current object—the object whose method or constructor is being called. It is most commonly used to disambiguate between instance variables and parameters when they have the same name. For example, if a constructor parameter is named `name` and the instance variable is also named `name`, you would write `this.name = name;` to assign the value from the parameter to the instance variable. The `this` keyword can also be used to call another constructor from within a constructor, a practice known as constructor chaining (`this(...)`), which helps to reduce code duplication.