The options classes define in com.mongodb.client.model use fluent setter methods, so that all options can be set without first assigning an instance of the options class to a variable, e.g.

// Java
collection.updateMany(Filters.eq("x", 1), Updates.set("x", 2),
            UpdateOptions()
                .upsert(true)
                .bypassDocumentValidation(true));

This is convenient for Java, but in Kotlin there is a more natural idiom that could be used if each option were exposed as a standard Java Bean-style setter:

// Kotlin
collection.updateMany(Filters.eq("x", 1), Updates.set("x", 2),
        UpdateOptions().apply {
            upsert = true
            collation = Collation.builder().backwards(true).build()
            bypassDocumentValidation = true
        });

which makes use of the <T> T.apply(block: T.() -> Unit): T extension function in the Kotlin standard library.