throw new Exception("Class is numeric!");
throw new UnsupportedClassTypeException("Class is numeric!");
  public void buildClassifier(Instances data) throws Exception{   if (data.classAttribute().isNumeric())      throw new Exception("Class is numeric!");   if (data.checkForStringAttributes()) {     throw new Exception("Can't handle string attributes!");   }   data = new Instances(data);   data.deleteWithMissingClass();   buildTree(data, m_subtreeRaising);   collapse();   if (m_pruneTheTree) {     prune();   }   if (m_cleanup) {     cleanup(new Instances(data, 0));   }  }