A DESCRIPTION OF THE PROBLEM :
There are three typos in the example given at the top.
1. Remove the second left brace in the  " catch ... "  line.
2. Terminate  " JComponent editor = spinner.getEditor() "  with a semicolon.
3. A closing parenthesis is missing before the semicolon in
 " ((DefaultEditor)editor).getTextField().setValue(spinner.getValue(); " 

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
try {
       spinner.commitEdit();
   }
   catch (ParseException pe) {
       // Edited value is invalid, spinner.getValue() will return
       // the last valid value, you could revert the spinner to show that:
       JComponent editor = spinner.getEditor();
       if (editor instanceof DefaultEditor) {
           ((DefaultEditor)editor).getTextField().setValue(spinner.getValue());
       }
       // reset the value to some known value:
       spinner.setValue(fallbackValue);
       // or treat the last valid value as the current, in which
       // case you don't need to do anything.
   }
   return spinner.getValue();
ACTUAL -
See above.

URL OF FAULTY DOCUMENTATION :
http://docs.oracle.com/javase/7/docs/api/