Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "Select Month"

Question

I was trying to develop a calendar app in java swing. I have 3 JComboBoxes, where you can select the year, month and day, and I keep getting this error every time I try to select a year:

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "Select Month"
    at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
    at java.base/java.lang.Integer.parseInt(Integer.java:652)
    at java.base/java.lang.Integer.parseInt(Integer.java:770)
    at calendar.Show$1.itemStateChanged(Show.java:315)
    at java.desktop/javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1227)
    at java.desktop/javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1279)
    at java.desktop/javax.swing.JComboBox.contentsChanged(JComboBox.java:1335)
    at java.desktop/javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:123)
    //......//

I think think the problem is in this part of my code:

jcbyear3.addItemListener (new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent arg0) {
                int y = Integer.parseInt(String.valueOf(arg0.getItem())); 
                //String mont= String.valueOf(monthjcb.getSelectedItem());
               
                String monthin = String.valueOf(monthjcb.getSelectedItem());
                String mont = monthin == null || monthin.isEmpty() || monthin.equals("Select Month") ? "January" : monthin;
                    
                    
                //int d=Integer.parseInt(String.valueOf(dayjcb.getSelectedItem()));
                    
                String dayin = String.valueOf(monthjcb.getSelectedItem());
                int d = dayin == null || dayin.isEmpty() || dayin.equals("Select Day") ? 1 :Integer.parseInt(dayin) ;
             
                    
                
                int m=0;
                if(mont.equals("January")) {
                    m=1;
                }
                else if(mont.equals("February")) {
                    m=2;
                }
                //.....//

                String[] h=store.search(y, m, d);
                if(h[0].equals("0"))
                    dayarea.setText("No events found");
                else if(h[0].equals("1")){
                    dayarea.setText(h[1]);
                }
                else if(h[0].equals("2")){
                    dayarea.setText(h[1]+"\n"+h[2]);
                }
                else if(h[0].equals("3")){
                    dayarea.setText(h[1]+"\n"+h[2]+"\n"+h[3]);
                }
                else {
                    dayarea.setText(h[1]+"\n"+h[2]+"\n"+h[3]+"\n"+h[4]+"\n"+h[5]);
                }
                
            }
        });

Could someone please help me to correct my problem?

Answer 1

This line

 String monthin = String.valueOf(monthjcb.getSelectedItem());

is returning you "Select Month"

then for the day you are asking again for the same stuff (i.e., monthjcb.getSelectedItem()):

String dayin = String.valueOf(monthjcb.getSelectedItem());

so dayin = "Select Month" and because of that you will reach in the conditional:

int d = dayin == null || dayin.isEmpty() || dayin.equals("Select Day") ? 1 :Integer.parseInt(dayin) ;

this part Integer.parseInt(dayin)

leading to java.lang.NumberFormatException: For input string: “Select Month” since you are trying to extract an Integer from a String that does not contain a number value encoded.

Base on your commented out line, I would say that instead of:

String dayin = String.valueOf(monthjcb.getSelectedItem());

you probably want:

String dayin = String.valueOf(dayjcb.getSelectedItem();