How does the absence of parameters in the constructor of a data class affect its behavior or functionality?

In Android (Kotlin), a data class without constructor parameters is a class that does not contain properties defined through the constructor. This affects functionality as follows:

• Automatically generated methods equals(), hashCode(), toString(), copy(), and componentN() will work with an empty set of properties.
• Such a data class essentially contains no data, and its use is limited.
• It can be used as a marker or for extension, but loses its meaning as a data container.

Example:

data class EmptyData()

fun main() {
    val e1 = EmptyData()
    val e2 = EmptyData()
    println(e1 == e2) // true, since there are no properties to compare
    println(e1.toString()) // EmptyData()
}

Thus, the absence of constructor parameters makes a data class more of a formal construct, without useful data inside.