title: OpenCV 3.0.0 FaceDetect Sample fails
body: <p>I am trying to get OpenCV running i am using the following 
  <a href="http://docs.opencv.org/trunk/doc/tutorials/introduction/desktop_java/java_dev_intro.html">sample code</a></p>
  
  <p>I get the following Error line displayed:</p>
  
  <pre><code>OpenCV Error: Assertion failed (!empty()) in cv::CascadeClassifier::detectMultiScale, file ..\..\..\..\opencv\modules\objdetect\src\cascadedetect.cpp, line 1580
  Exception in thread "main" CvException [org.opencv.core.CvException: cv::Exception: ..\..\..\..\opencv\modules\objdetect\src\cascadedetect.cpp:1580: error: (-215) !empty() in function cv::CascadeClassifier::detectMultiScale
  ]
      at org.opencv.objdetect.CascadeClassifier.detectMultiScale_1(Native Method)
      at org.opencv.objdetect.CascadeClassifier.detectMultiScale(CascadeClassifier.java:176)
      at org.maxbit.opencv.samples.DetectFaceDemo.run(SampleB.java:29)
      at org.maxbit.opencv.samples.SampleB.main(SampleB.java:51)
  </code></pre>
  
  <p>Can any body tell me what that error means or how to debug this?</p>