CustomJacksonModule for Finatra with CamelCase strategy, default finatra jackson module uses SNAKE_CASE as namin strategy

CustomJacksonModule.scala

import com.fasterxml.jackson.annotation.JsonInclude.Include
import com.fasterxml.jackson.core.JsonGenerator.Feature
import com.fasterxml.jackson.databind.ObjectMapper
import com.twitter.finatra.json.modules.FinatraJacksonModule
import com.twitter.finatra.json.utils.CamelCasePropertyNamingStrategy

object CustomJacksonModule extends FinatraJacksonModule {

  override val serializationInclusion = Include.ALWAYS

  override val propertyNamingStrategy = CamelCasePropertyNamingStrategy

  override def additionalMapperConfiguration(mapper: ObjectMapper) {
    mapper.configure(Feature.WRITE_NUMBERS_AS_STRINGS, true)
  }
}

In your FinatraServer class you need to override:
override def jacksonModule = CustomJacksonModule