code: public void addColumns(ArrayList<String> columns, String defaultValue) {
  		CompactCharSequence dv = new CompactCharSequence(defaultValue);
  		for (int i = 0; i < data.length; i++) {
  			CompactCharSequence[] row = data[i];
  			int oldrowlength = data[i].length;
  			data[i] = (CompactCharSequence[]) resizeArray(row, oldrowlength + columns.size());
  			for (int c = 0; c < columns.size(); c++) {
  				data[i][oldrowlength + c] = dv;
  			}
  			if (i == 0) {
  				for (int c = 0; c < columns.size(); c++) {
  					String column = columns.get(c);
  					data[0][oldrowlength + c] = new CompactCharSequence(column);
  					columnLookup.put(column, new HeaderInfo(oldrowlength + c));
  				}
  			}
  		}
  		//   columnLookup.get("ZNF30");
  
  		//     int startIndex = columnLookup.size() + 1;
  		//     for (String column : columns) {
  		//        if(column.equals("ttr")){
  		//            int dummy = 1;
  		//        }
  		//        columnLookup.put(column, new HeaderInfo(startIndex));
  		//        startIndex++;
  		//    }
  
  
  	}
docs: Add columns to worksheet and set default value
  
  @param columns
  @param defaultValue