code: public String getColumnNames() {
  		StringBuffer sb = new StringBuffer();
  		int lvSize = columnNames.size();
  		for (int i=0;i<lvSize; i++) {
  			sb.append(columnNames.get(i));
  			if (i < (lvSize-1)) {
  				sb.append(getDelimiter());
  			}			
  		}
  		return sb.toString();
  	}
docs: Get all column - names as String, separated with a selected delimiter.
  @return All column - names as String.