You could return an Integer instead of an int, returning null on parse failure.

It's a shame Java doesn't provide a way of doing this without there being an exception thrown internally though - you can hide the exception (by catching it and returning null), but it could still be a performance issue if you're parsing hundreds of thousands of bits of user-provided data.

EDIT: Code for such a method:

public static Integer tryParse(String text) {
  try {
    return Integer.parseInt(text);
  } catch (NumberFormatException e) {
    return null;
  }
}

Note that I'm not sure off the top of my head what this will do if text is null. You should consider that - if it represents a bug (i.e. your code may well pass an invalid value, but should never pass null) then throwing an exception is appropriate; if it doesn't represent a bug then you should probably just return null as you would for any other invalid value.

Originally this answer used the new Integer(String) constructor; it now uses Integer.parseInt and a boxing operation; in this way small values will end up being boxed to cached Integer objects, making it more efficient in those situations.

public static boolean isParsable(String input) {
    try {
        Integer.parseInt(input);
        return true;
    } catch (final NumberFormatException e) {
        return false;
    }
}

Here is the regular code to use Interger.parseInt():

try {
    Integer.parseInt(string);
} catch (NumberFormatException e) {
    //code
}

But you could use the following (it catches all exceptions):

try {
    Integer.parseInt(string);
} catch (Exception e) {
    //code
}

Is that your question?

Because the result will get greater than Integer.MAX_VALUE

Try this

System.out.println(Integer.parseInt("yellow", 35));
System.out.println(Long.parseLong("howareyou", 35));

and for

Long.parseLong("abcdefghijklmno",25)

you need BigInteger

Try this and you will see why

System.out.println(Long.MAX_VALUE);
System.out.println(new BigInteger("abcdefghijklmno",25));

Your field is empty and you are trying to convert an empty string into a number (via parseInt()). That's what is causing the NumberFormatException.

To avoid that kind of exception, you should validate your field. You can write a simple check testing if it's empty by asserting that the length() of the input String returned by getText() is greater than zero.

You can check if it is a number writing a regular expression

String possibleNumber = yourField.getText();
boolean isNumber = Pattern.matches("[0-9]+", possibleNumber);
if(isNumber) {
   number = Integer.parseInt(possibleNumber);
}

But you shouldn't be reading data in the constructor in the first place. Write an event handler to capture the action event of pressing the button, and in it read the data.

yourButton.addActionListener(new ActionListener() {
    yourText = field.getText();
});