[JAVA] JWT Bearer token auth not implemented

Description

Defining a security scheme as type: bearer does not generate an appropriate OkHttpClient Interceptor. It has OAuth2, Basic & ApiKey but not any others.

Swagger-codegen version

3.0.34

Swagger declaration file content or url

    ...
    "securitySchemes": {
      "Bearer": {
        "type": "http",
        "description": "Bearer Authentication with JWT Token",
        "scheme": "bearer",
        "bearerFormat": "JWT"
      }
    },
    "security": [
      {
        "Bearer": []
      }
    ]

Command line used for generation

{
    "modelPackage": "redacted",
    "apiPackage": "redacted",
    "artifactId": "redacted",
    "artifactVersion": "1.0.0",
    "library": "retrofit2",
    "useRxJava2": "true",
    "dateLibrary": "java8",
    "java8": "true"
}

Steps to reproduce

Related issues/PRs

Suggest a fix/enhancement

Add a simple Interceptor that adds the Authorization: Bearer <token> header and make ApiClient#setAccessToken look for that interceptor.

BearerTokenAuth.java

import java.io.IOException;

import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;

public class BearerTokenAuth implements Interceptor {

    private String token;

    public String getAccessToken() {
        return token;
    }

    public void setAccessToken(String token) {
        this.token = token;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();

        // If the request already have an authorization (eg. Basic auth), do nothing
        if (request.header("Authorization") == null) {
            request = request.newBuilder()
                    .addHeader("Authorization", "Bearer " + token)
                    .build();
        }
        return chain.proceed(request);
    }
}

ApiClient.java

public ApiClient(String[] authNames) {
    this();
    for (String authName : authNames) {
        Interceptor auth = null;
        if ("Bearer".equals(authName)) {
            auth = new BearerTokenAuth();
        } else {
            throw new RuntimeException("auth name \"" + authName + "\" not found in available auth names");
        }

        addAuthorization(authName, auth);
    }
}
...
/**
     * Helper method to pre-set the oauth access token of the first oauth found in the apiAuthorizations (there should be only one)
     *
     * @param accessToken Access token
     * @return ApiClient
     */
    public ApiClient setAccessToken(String accessToken) {
        for (Interceptor apiAuthorization : apiAuthorizations.values()) {
            if (apiAuthorization instanceof OAuth) {
                OAuth oauth = (OAuth) apiAuthorization;
                oauth.setAccessToken(accessToken);
                return this;
            } else if (apiAuthorization instanceof BearerTokenAuth) {
                final BearerTokenAuth bearerTokenAuth = (BearerTokenAuth) apiAuthorization;
                bearerTokenAuth.setAccessToken(accessToken);
                return this;
            }
        }
        return this;
    }

Start by locating the Java retrofit2 templates or generated ApiClient.java and compare the existing OAuth, Basic, and ApiKey interceptor handling. Review the proposed BearerTokenAuth.java and ApiClient#setAccessToken behavior, then verify that an OpenAPI bearer security scheme generates the interceptor and applies the Authorization header.