Constructor overload

Coming from another language, you may be tempted to declare multiple constructors for your classes. For instance, let’s look at a definition of a User class in Java:

class User {
    private final String name;
    private final boolean resetPassword;
 
    public User(String name) {
        this(name, true);
    }
 
    public User(String name, boolean resetPassword) {
        this.name = name;
        this.resetPassword = resetPassword;
    }
}

Here, the User class has two constructors, one of which sets a default value for resetPassword.

Kotlin simplifies this pattern significantly using the default and secondary constructors or leveraging default parameter values:

class User(val name: String, val resetPassword: Boolean) {
    constructor(name: String) : this(name, true)
}

The secondary constructor here calls the primary constructor, setting a default value for resetPassword.

However, it’s usually better to have default...