[BUG] [Java] Default Java client does not compile

Created by: rizwansaeed

Bug Report Checklist

Have you provided a full/minimal spec to reproduce the issue?
Have you validated the input using an OpenAPI validator (example)?
What's the version of OpenAPI Generator used?
Have you search for related issues/PRs?
What's the actual output vs expected output? Generated client successfully compiles, currently fails due to missing imports

Description

Generating a Java client using the default options produces code that does not compile. A sample swagger file is provided that reproduces the issue. It appears that some model classes are not included as required dependencies, manually adding them (as imports to the generated code) resolves the issue. Note that the sample is only a subset of the full swagger file, other model and API classes generate successfully but there appears to be something in this example that causes it not work.

Also note that the C# client generates successfully which suggests that the swagger file itself is ok

openapi-generator version

4.0.0-SNAPSHOT (via Docker image)

OpenAPI declaration file content or url

https://gist.github.com/rizwansaeed/a8413c9dd55715b1a6e71fce93f2f89c

Command line used for generation

docker run --rm -v ${PWD}:/local openapitools/openapi-generator-cli generate \
    -i /local/sample.json \
    -g java \
    -o /local/out/src

Steps to reproduce

Run the command line above
Try to build the project

Suggest a fix

The generated code should include imports for all dependencies