[BUG] [JAVA][Native] Variable already exists (Exception variable)

Description

While generating for Java native we get an invalid code, which looks like this:

public ApiResponse<Void> collectGetWithHttpInfo(..., String e, ...) throws ApiException {
    HttpRequest.Builder localVarRequestBuilder = collectGetRequestBuilder(..., e, ...);
    try {
      HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
          localVarRequestBuilder.build(),
          HttpResponse.BodyHandlers.ofInputStream());
      if (memberVarResponseInterceptor != null) {
        memberVarResponseInterceptor.accept(localVarResponse);
      }
      try {
        if (localVarResponse.statusCode()/ 100 != 2) {
          throw getApiException("collectGet", localVarResponse);
        }
        return new ApiResponse<Void>(
          localVarResponse.statusCode(),
          localVarResponse.headers().map(),
          null
        );
      } finally {
        // Drain the InputStream
        while (localVarResponse.body().read() != -1) {
            // Ignore
        }
        localVarResponse.body().close();
      }
    } catch (IOException e) {
      throw new ApiException(e);
    }
    catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      throw new ApiException(e);
    }
  }

As you can see there is a method parameter "e" and the Exceptions "e" which hold the same name.

openapi-generator version

7.1.0

OpenAPI declaration file content or url

Our spec contains something like:

...
{
            "in": "query",
            "name": "e",
            "required": true,
            "schema": {
              "type": "string",
              "enum": [
                "conversion:summary",
                "conversion:item"
              ]
            }
          },
...

Generation Details

Steps to reproduce

configuration looks as follows:

<execution>
                        <id>some-service</id>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>openapi.json</inputSpec>
                            <generatorName>java</generatorName>
                            <skipValidateSpec>true</skipValidateSpec>
                            <library>native</library>
                            <generateModelTests>false</generateModelTests>
                            <generateApiTests>false</generateApiTests>
                            <configOptions>
                                <dateLibrary>legacy</dateLibrary>
                                <sourceFolder>src/gen/java/main</sourceFolder>
                                <packageName>ch.x.y</packageName>
                                <apiPackage>ch.x.y</apiPackage>
                                <modelPackage>ch.x.y.model</modelPackage>
                                <invokerPackage>ch.x.y</invokerPackage>
                            </configOptions>
                        </configuration>
                    </execution>

Suggest a fix

Give exceptions an unique name within the block or give everything else an prefix.

Reproduce the issue with an OpenAPI query parameter named e and the Java generator using the native library. Inspect the Java native generator's exception and parameter naming logic, then verify that generated methods compile and that a regression test covers the conflicting name.