title: Invalid Date format in Post request using swagger code gen (open api)
body: <p>Hi I am using swagger code gen (v3) to generate the service client in my Spring Boot project using the following configuration in my pom.xml</p>
  
  <pre><code>&lt;configuration&gt;
      &lt;language&gt;java&lt;/language&gt;
      &lt;inputSpec&gt;specs.yaml&lt;/inputSpec&gt;
      &lt;apiPackage&gt;api&lt;/apiPackage&gt;
      &lt;modelPackage&gt;model&lt;/modelPackage&gt;
      &lt;invokerPackage&gt;invoker&lt;/invokerPackage&gt;
      &lt;generateApis&gt;true&lt;/generateApis&gt;
      &lt;generateApiTests&gt;false&lt;/generateApiTests&gt;
      &lt;generateApiDocumentation&gt;false&lt;/generateApiDocumentation&gt;
      &lt;generateSupportingFiles&gt;true&lt;/generateSupportingFiles&gt;
      &lt;generateModelDocumentation&gt;false&lt;/generateModelDocumentation&gt;
      &lt;generateModelTests&gt;false&lt;/generateModelTests&gt;
      &lt;typeMappings&gt; 
          &lt;typeMapping&gt;DateTime=LocalDateTime&lt;/typeMapping&gt;
          &lt;typeMapping&gt;Date=LocalDate&lt;/typeMapping&gt;
      &lt;/typeMappings&gt;
      &lt;importMappings&gt; 
          &lt;importMapping&gt;LocalDateTime=java.time.OffsetDateTime&lt;/importMapping&gt;
          &lt;importMapping&gt;LocalDate=java.time.LocalDate&lt;/importMapping&gt;
      &lt;/importMappings&gt;
      &lt;configOptions&gt;
          &lt;library&gt;resttemplate&lt;/library&gt;
          &lt;interfaceOnly&gt;true&lt;/interfaceOnly&gt;
          &lt;useTags&gt;true&lt;/useTags&gt;
          &lt;useBeanValidation&gt;true&lt;/useBeanValidation&gt;
          &lt;dateLibrary&gt;java8&lt;/dateLibrary&gt;
          &lt;java8&gt;true&lt;/java8&gt;
          &lt;sourceFolder&gt;/&lt;sourceFolder&gt;
      &lt;/configOptions&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Issue I am facing is while performing the POST request through the Api Client generated through above configuration. POST request looks like</p>
  
  <pre><code>{
      "name": "abc",
      "type": "xyz",
      "businessdata": {
          "currency": "INR",
          "startDate": [2020,5,28],
          "endDate": [2021,12,25],
          "code": "X123"
      },
      "seqnumber": "987"
  
  }
  </code></pre>
  
  <p>Here <strong>startDate</strong> and <strong>endDate</strong> are <strong>LocalDate in Java class</strong> and those are also generated by Open Api specs. Here I am not understanding why it is converting to <strong>brackets []</strong> and hence <strong>other system which is receiving this request is throwing invalid date exception</strong>.</p>
  
  <p>Please let me know how to fix this issue and explain in detail as I am new to swagger code gen.</p>