/** * Calculate frequency of each character * * @param evt */ private void btn_frequencyActionPerformed(ActionEvent evt) { String input = taInput.getText(); Map<Character, Integer> character_frequency_unsorted = calc.count_characters(input); character_frequency = calc.sort_characters(character_frequency_unsorted); StringBuilder sb = new StringBuilder(); for (Entry<Character, Integer> entry : character_frequency.entrySet()) { sb.append(entry.getKey()).append(" = ").append(entry.getValue()).append("\n"); } taOutput.setText(sb.toString()); }