title: ObjectMapper cannot be resolved to a type
body: <p>I have troubles getting JSON to work. <code>ObjectMapper</code> cannot be resolved. Library is imported correctly.</p>
  
  <pre><code>import java.io.File;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import net.sf.json.JSONException;
  import net.sf.json.util.*;
  
  import com.fasterxml.jackson.*;
  
  public class Json {
      private static final String jsonFilePath = "C:\\Users\\Juergen\\Desktop\\filesForExamples\\mapExample.json";
  
      public static void objectToJSON(HashMap&lt;String, Mat&gt; map) {
          //Map&lt;String, Object&gt; mapObject = new HashMap&lt;String, Object&gt;();
          ObjectMapper mapper = new ObjectMapper();
  
          try {
              objectMapper.writeValue(new File(jsonFilePath), map);
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  }
  </code></pre>