[BUG][jaxrs-spec] When using the "jackson" option to disable use of Jackson, some jackson annotations and imports are still generated

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?
• [Optional] Bounty to sponsor the fix (example)

Description

When using the jaxrs-spec server generator with the option "jackson" set to "false", I expect the generated code to not contain any imports or annotations referring to Jackson. Instead the code is generated with many Jackson annotations. This can be seen when using the test spec "modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml" as input, for example in generated class FormatTest.java.

It is also evident, when looking at the template files, that use Jackson unfenced:

In modules/openapi-generator/src/main/resources/JavaJaxRS/spec:

• enumClass.mustache
• enumOuterClass.mustache
• pojo.mustache
• pom.mustache

And in:

• modules/openapi-generator/src/main/resources/JavaJaxRS/spec/libraries/openliberty/pom.mustache

openapi-generator version

Latest 5.0.0-SNAPSHOT

Suggest a fix

I will open a PR with the fix.

Start with enumClass.mustache, enumOuterClass.mustache, pojo.mustache, pom.mustache, and libraries/openliberty/pom.mustache under modules/openapi-generator/src/main/resources/JavaJaxRS/spec. Use petstore-with-fake-endpoints-models-for-testing.yaml and inspect generated FormatTest.java with the jackson option disabled. Done means the generated code contains no Jackson imports or annotations.