[BUG][JAVA] Unnecessary Jackson imports added to oneOf interface when non-Jackson library is used

[DavidGrath]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

The generator adds unnecessary Jackson imports to a oneOf interface when using retrofit2 and gson, which causes a build error because of the non-existent package

openapi-generator version

7.13.0

OpenAPI declaration file content or url

Reusing oneOf.yaml

Generation Details

Config:

library: 'retrofit2'
useOneOfInterfaces: true

Command:

java -jar openapi-generator-cli.jar generate -g java -i oneOf.yaml -c config.yaml -o out

Steps to reproduce

./gradlew.bat build

Expected output

// Other imports
// No Jackson Imports
public interface Fruit  {
}

Actual output

// Other imports
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

public interface Fruit  {
}

Related issues/PRs

Suggest a fix

PR Incoming

[DavidGrath]

#21405
@martin-mfg