[BUG] [JavaJaxRS] Using `generateBuilders=true` breaks generated models

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Switching generateBuilders on, for an example Spec like follows:

      "ExampleWrapper": {
        "type": "object",
        "properties": {
          "street": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      }

leads to code lke this:

public class ExampleWrapper {
[...]
  private @Valid String street;

  public ExampleWrapper(){
  }

  private @Valid String name;

  public ExampleWrapper(){
  }

[...methods...]
[...builder definition...]

As one can see, the same no-arg-constructor is created over and over, leading to compile errors.

openapi-generator version

5.4.0 (should also appear in older 5.x versions, haven't tracked any further)

OpenAPI declaration file content or url

Generation Details

openapi-generator-maven-plugin:5.4.0
with config:

                        <configuration>
                            <inputSpec>${project.basedir}/src/main/resources/META-INF/openapi.json</inputSpec>
                            <configurationFile>${project.basedir}/src/main/openapi/generator/configuration.json</configurationFile>
                            <apiPackage>com.example.api.generated</apiPackage>
                            <modelPackage>com.example.api.generated.model</modelPackage>
                            <generatorName>jaxrs-spec</generatorName>
                            <configOptions>
                                <interfaceOnly>true</interfaceOnly>
                                <returnResponse>false</returnResponse>
                                <sourceFolder>java</sourceFolder>
                                <useSwaggerAnnotations>false</useSwaggerAnnotations>
                                <generatePom>false</generatePom>
                                <dateLibrary>java8</dateLibrary>
                                <generateBuilders>true</generateBuilders>
                            </configOptions>
                        </configuration>

Steps to reproduce

see above

Related issues/PRs

Suggest a fix

moving the section...

  {{#generateBuilders}}public {{classname}}({{#vars}}{{{datatypeWithEnum}}} {{name}}{{^-last}}, {{/-last}}{{/vars}}) {
    {{#vars}}
    this.{{name}} = {{name}};
    {{/vars}}
  }{{/generateBuilders}}

...from here: https://github.com/OpenAPITools/openapi-generator/blob/v5.4.0/modules/openapi-generator/src/main/resources/JavaJaxRS/spec/pojo.mustache#L39-L43

...up a few lines, to be outside of the other {{#vars}}-loop. How about here: https://github.com/OpenAPITools/openapi-generator/blob/v5.4.0/modules/openapi-generator/src/main/resources/JavaJaxRS/spec/pojo.mustache#L22

I am puzzled that is ever worked, given the inital commit https://github.com/OpenAPITools/openapi-generator/commit/62c346f8da5a8f643396b48e8bfe5d0bc482793c already created constructors inside the "property rendering loop", so for n properties, it should've rendered n identical constructors!?

Start with modules/openapi-generator/src/main/resources/JavaJaxRS/spec/pojo.mustache, especially the generateBuilders constructor block and its surrounding vars loop. Reproduce with the supplied JavaJaxRS Maven configuration and confirm that a model with multiple properties generates only one no-argument constructor and compiles without duplicate-constructor errors.