Assume the existence of the following Java GUI application. There are two text fields for user input. The first JTextField variable is named res1 and is used to input a resistance value in ohms. The second JTextField variable named res2 is used to input a second resistance value in ohms. All input values and calculations use integer values. The user clicks a JButton to perform a calculation. One JButton called series causes the program to calculate and display the series resistance of the 2 resistors, RT = R1 + R2. Another JButton called parallel causes the program to calculate the parallel resistance of the 2 resistors, RT = (R1 * R2)/(R1 + R2). The result of the selected calculation is displayed in an output text area variable named output. The output string should say something like this: “Total resistance of 100 and 200 ohms in series is 300 ohms.” Clicking one of the buttons generates the event which causes the program to do the selected calculation and update the output area. Assume the user interface has already been implemented and the member variables listed above exist. Your job is to write the ButtonHandler inner class which handles the events from the two buttons, does the requested calculation and displays the appropriate result.