Time validator

Question

I am trying to come up with some way of producing an applet that will deal with the following:
In this task you are required to design, create and test a new class called newTime.
1. Design a solution for a new class called newTime.      
a. public boolean valid24Time (int hh, int mm)
     The hours (hh) can only be in the range 0-23 and the
minutes (mm) can only be in the range 0-59.
     This method must return true if the time is valid and false
if the time is invalid.
     b. public String convert24ToStd (int hh, int mm)
     The time is passed to the method as hours (hh) and minutes
(mm)with the time in 24
     hour format. The 24 hour format must be changed into standard
format in the form
     hh:mm AM for a morning time and hh:mm PM for an afternoon time.
     This method must return a string containing the time in
standard format.
     c. public int convertStdTo24 (String hhmm)
     The time is passed to the method as a string in standard format
in the form hh:mm
     AM for a morning time and hh:mm PM for an afternoon time. The
standard format     must be changed into 24 hour format.
     This method must return an integer containing the time in 24
hour format.
     d. public int addTime (int hh1, int mm1, int hh2, int mm2)
     Two times are passed to the method in 24 hour format as hours
and minutes (hh1 and mm1, hh2 and mm2). The two times must be
added together.
     This method returns the calculated time as an integer in 24
hour format.
     e. public int subtractTime (int hh1, int mm1, int hh2, int mm2)
     Two times are passed to the method in 24 hour format as hours
and minutes (hh1 and mm1, hh2 and mm2). The second time must be
subtracted from the first.
     This method must return the calculated time as an integer in 24
hour format.
2. Error handling routines must be included to deal with exceptions.
3. Write the code for the newTime class.
4. Design and create a testnewTime class which tests the methods in the newTime class.
Document the layout of any input and output screens used.
5. Create test data to test the newTime class and determine the expected results.
6. Prepare a test plan.
7. Test the software, compare the actual results to the expected results keeping a log for
each test which identifies any discrepancies between actual and expected results and
records any amendments made to correct errors.
8. Produce technical documentation to describe the class interface and purpose and
operation of the newTime class.
9. Produce a printed program listing.
Any help would be grateful
Regards
Rary Geddi

Answer 1

I've have tried all ways to get this to work but with out any luck.
What am I doing wrong?
public class Frame1 extends JFrame {
String inputHour;
String inputMin;
int hh = 0;
int mm = 0;
boolean isHourValid;
boolean isMinValid;
public boolean valid24Time ( int hh, int mm)
{  boolean isHourValid = ( hh>= 0 && hh<24);
boolean isMinValid = ( mm>= 0 && mm <60);
return (isHourValid & isMinValid);
private JPanel contentPane;
private JPanel jPanel1 = new JPanel();
private JButton jButton1 = new JButton();
private JButton jButton2 = new JButton();
private JButton jButton3 = new JButton();
private JButton jButton4 = new JButton();
private JButton jButton5 = new JButton();
private GridBagLayout gridBagLayout1 = new GridBagLayout();
private GridBagLayout gridBagLayout2 = new GridBagLayout();
void jButton1_actionPerformed(ActionEvent e) {
inputHour = JOptionPane.showInputDialog("Enter Hour");
hh = Integer.parseInt(inputHour);
inputMin = JOptionPane.showInputDialog("Enter minute");
mm = Integer.parseInt(inputMin);
if ( isHourValid & isMinValid )
JOptionPane.showMessageDialog
(null,"Time invalid" hh mm,"Invalid time", JOptionPane.PLAIN_MESSAGE);
else
JOptionPane.showMessageDialog
(null, "Time valid" hh mm, "Valid time", JOptionPane.PLAIN_MESSAGE);
}