Unchecked conversion warning in `JsonMapper`

[ilgrosso]

Describe your Issue

When defining a class like as

public class SyncopeJsonMapper extends JsonMapper {
...
}

(since I need to override some methods), I am getting the build warning as follows:

[WARNING] readTree(tools.jackson.core.JsonParser) in tools.jackson.databind.ObjectMapper implements <T>readTree(tools.jackson.core.JsonParser) in tools.jackson.core.TreeCodec
  return type requires unchecked conversion from tools.jackson.databind.JsonNode to T

This happens with 3.0.3.

Adding

@SuppressWarnings("unchecked")

does not seem to help.