UserConstructorExample.kt

class User {

    val firstName: String
    val middleName: String? // optional
    val lastName: String
    val address: Address
    val contact: Contact? // optional
    val company: Company? // optional
    val educations: List<Education>

    constructor(
        firstName: String,
        middleName: String?,
        lastName: String,
        address: Address,
        contact: Contact?,
        company: Company?,
        educations: List<Education>
    ) {
        this.firstName = firstName
        this.middleName = middleName
        this.lastName = lastName
        this.address = address
        this.contact = contact
        this.company = company
        this.educations = educations
    }
}