[BUG][Java] ApiClient.basePath is not a path but an URL

Bug Report Checklist

Description

The ApiClient generated for Java looks like this:

@Component("some.package")
public class ApiClient extends JavaTimeFormatter {
    private boolean debugging = false;
    private HttpHeaders defaultHeaders = new HttpHeaders();
    private MultiValueMap<String, String> defaultCookies = new LinkedMultiValueMap();
    private String basePath = "https://example.org";
    // ...

with string-based getters and setters. But the naming is wrong imho. That's not a path but a (base) URL.

openapi-generator version

5.0.0-beta2

OpenAPI declaration file content or url

not required - use petstore

Generation Details

Steps to reproduce

Generate the petstore example for java, look at the ApiClient.

Related issues/PRs

Suggest a fix

1. Rename into baseUrl with getBaseUrl and setBaseUrl.
2. Replace String with java.net.URL - the only usage (in my case) seems to be in ApiClient.buildUrl().

Generate the petstore example for Java and inspect the generated ApiClient, including its basePath accessors and the buildUrl usage. Confirm whether the intended fix is a naming change, a java.net.URL type change, or both; done means the generated client uses the agreed base URL API consistently.