How is the strategy for handling missing data or cases implemented in the system?

In Android, the pattern Optional (for example, the Optional class in Java or Nullable types in Kotlin) is often used to handle missing data or cases. It explicitly indicates that a value may be absent and forces the developer to handle this case.

Other approaches include:

• Using null with checks and safe calls (?. in Kotlin).
• Returning special values or stub objects (Null Object pattern).
• Error handling through exceptions or Result objects that contain either data or error information.

An example in Kotlin using a nullable type and safe call:

fun getUserName(userId: String): String? {
    val user = database.findUserById(userId)
    return user?.name // returns null if user == null
}

val name = getUserName("123") ?: "Name not found"
println(name)

Thus, the strategy boils down to explicitly accounting for missing data and safely handling such cases to avoid failures and ensure correct application operation.