There are several ways; here is a relatively easy one. It will check that the input is not empty but will not verify that the input meets any particular requirements. Assuming you have three text fields called nameField, ageField, and addressField, just do something like this:
You could also check the name, age, and address separately using three if statements and then have specific messages such as "The name must be filled", etc.
Joined: Jul 22, 2005
but under which public void shd i add the coding given?
also does e following coding applies to applet?? JOptionPane.showMessageDialog(null, "All fields must be filled");