I'm getting a NullPointerException for a java GUI for a warning message scenario if no data is added in GUI

Question

I am fairly new to Java GUI so ANY help you give is greatly appreciated.

There is a scenario for showing warning message if not data is entered in GUI. These warning messages are displayed in the GUI however soon after that program fails with a NullPointerException

private void addActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:

    String tempdate = date.getText();
    if(tempdate.isEmpty() ){
        datelabel.setVisible(true);            
    }
    String tempttl = total.getText();
    if(tempttl.isEmpty() ){
        totallabel.setVisible(true);
        typelabel.setVisible(true);

    }
    String temptype = null;
    if (rain.isSelected()){
        temptype = rain.getText();
    }
    if (snow.isSelected()){
        temptype = snow.getText();
    }
    if (sleet.isSelected()){
        temptype = sleet.getText();
    }
    if (hail.isSelected()){
        temptype = hail.getText();
    } 
    if (mixed.isSelected()){
        temptype = mixed.getText();
    }
    if(temptype.isEmpty() ){

        typelabel.setVisible(true);
    }
    if(tempdate.matches("^\\d{1,2}\\/\\d{1,2}\\/\\d{4}$")) {
        ArrayList <Precipclass> list = ListPrecipitation(tempdate,tempttl,temptype);
        Object rowdata[] = new Object[3];
        for (int i = 0; i < list.size(); i++) {
            rowdata[0]=list.get(i).pDate;
            rowdata[1]=list.get(i).pType;
            rowdata[2]=list.get(i).pTotal;
            model.insertRow(i, rowdata);
        }
    }

}