Why is itemStateChanged on JComboBox is called twice when changed?

Question

I\'m using a JComboBox with an ItemListener on it. When the value is changed, the itemStateChanged event is called twice. The first call, the ItemEvent is showing the origin

Answer 1

Have a look here,

box.addItemListener(new ItemListener(){
    public void itemStateChanged(ItemEvent e){
        if(e.getStateChange()== ItemEvent.SELECTED) {
            //this will trigger once only when actually the state is changed
            JOptionPane.showMessageDialog(null, "Changed");
        }
    }
});

When you select a new option, it will only once call the JOptionPane, indicating that the code there will be called once only.