title: What does the "Unrecognized token openapi" error mean when using OpenAPI Generator with OpenAPI 3.0?
body: <p>I have written an API definition in the OpenAPI 3.0 format (<a href="https://swagger.io/docs/specification/basic-structure/" rel="noreferrer">https://swagger.io/docs/specification/basic-structure/</a>). Now I'm trying to generate Java Spring objects as I was previously doing with a Swagger 2.0 definition and its associated Maven plugin.</p>
  
  <p>So far, I have a basic API definition that begins with:</p>
  
  <p><code>openapi: 3.0.0
       info:
       title: Demo API
       description: This is a basic REST API implementing the [Open API Specification](https://en.wikipedia.org/wiki/OpenAPI_Specification).
       version: 0.0.1</code></p>
  
  <p>In my <code>pom.xml</code> file I have added:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;dependency&gt;
    &lt;groupId&gt;org.openapitools&lt;/groupId&gt;
    &lt;artifactId&gt;openapi-generator-cli&lt;/artifactId&gt;
    &lt;version&gt;3.3.3&lt;/version&gt;
  &lt;/dependency&gt;
  </code></pre>
  
  <p>But when executing <code>mvn install</code>, I get this error:</p>
  
  <pre><code>com.fasterxml.jackson.core.JsonParseException: Unrecognized
       token 'openapi': was expecting ('true', 'false' or 'null')
       at [Source: definition\DEFINITION.yml; line: 1, column: 9]
  </code></pre>
  
  <p>Does anyone know where the problem is?</p>