title: java.lang.NoClassDefFoundError: org/apache/http/nio/conn/NHttpClientConnectionManager
body: <p>I currently have these jars:</p>
  
  <ul>
  <li>httpasyncclient-4.0-beta3.jar</li>
  <li>httpclient-4.5.jar</li>
  <li>httpclient-cache-4.5.jar</li>
  <li>httpclient-win-4.5.jar</li>
  <li>httpcore-4.3.jar</li>
  <li>httpcore-nio-4.1-beta2.jar</li>
  <li>httpmime-4.2.3.jar</li>
  <li>slf4j-api-1.7.12.jar</li>
  </ul>
  
  <p>My java method where the error comes from is:</p>
  
  <pre><code> private HttpResponse&lt;JsonNode&gt; jwtAuthPost(String assertion) throws UnirestException {
      HttpResponse&lt;JsonNode&gt; jsonResponse = Unirest.post(AUTH_URL)
                .header("accept", "application/json")
                .field("grant_type", JWT_GRANT_TYPE)
                .field("client_id", this.clientId)
                .field("client_secret", this.clientSecret)
                .field("assertion", assertion)
                .asJson();  //error here
  
      return jsonResponse;
  }
  </code></pre>
  
  <p>I'm guessing there is a plugin somewhere that I'm missing for this, but I can't seem to find it anywhere.</p>
  
  <p>Rest of Error Log</p>
  
  <pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/nio/conn/NHttpClientConnectionManager
    at com.mashape.unirest.http.HttpClientHelper.prepareRequest(HttpClientHelper.java:154)
    at com.mashape.unirest.http.HttpClientHelper.request(HttpClientHelper.java:134)
    at com.mashape.unirest.request.BaseRequest.asJson(BaseRequest.java:68)
  </code></pre>