title: Test a single instance in Weka
body: <p>Does weka require the test instances to have the class attribute.
  I have used a training set arff file to train the classifier. Now I want to test an instance (not from arff file, have to create by code) without the class attribute and predict the class.
  I found this link <a href="https://stackoverflow.com/q/8957926/1138148">Weka: How do I get the prediction value in java for a test instance?</a></p>
  
  <p>But my class attribute is a string 'Y' or 'N'. If evaluateModelOnce() returns double, what does it mean. Is it the class attribute or something else. i am using the weka API.</p>