Spring Boot uses ObjectMapper for JSON handling in the background, and defining a custom setup ensures consistency across services.By creating a custom bean of ObjectMapper, you can control JSON conversion and behavior in your Spring Boot application.Placing the ObjectMapper inside a @Configuration class gives full control over JSON handling throughout the application.Having a shared configuration for JSON behavior in Spring Boot services can be achieved by creating a separate library or module.Customizing ObjectMapper settings can include changing field naming strategies and setting date formats for readability.Allowing ObjectMapper to ignore unknown fields in JSON input makes the application more flexible and forgiving.Enabling pretty-printing in Jackson helps with readability during development and testing.Having a consistent ObjectMapper setup ensures uniform JSON behavior across all parts of a Spring Boot application.Shared ObjectMapper configuration simplifies maintenance and updates across multiple services.By defining a custom ObjectMapper early in the application context, Spring Boot will automatically apply consistent JSON behavior.