Some of the Gotchas that one needs to be careful about

1. Default Package - When a class doesn’t include a package declaration it is considered to be in the “default package”. The use of the “default package” is generally discouraged, and should be avoided. It can cause particular problems for Spring Boot applications that use @ComponentScan, @EntityScan or @SpringBootApplication annotations, since every class from every jar, will be read.

2. Unit Testing with WebMvcTest and JsonTest - A unit test class cannot have both @WebMcvTest and @JsonTest annotations. It is better to use ObjectMapper explicitly for conversion of JSON and POJOs.

3. Using Java 8 DateTime API - If response and request models have Java 8 DateTime API usage then below dependency has to be added, so that Jackson is able to convert json to correct type of DateTime object.

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.8.6</version>
</dependency>