Responding to User Input - Java 6 - page 349

The answer is available on the topic's website at http://www.java21days.com. Visit the
Day 12 page and click the Certification Practice link.
Exercises
To extend your knowledge of the subjects covered today, try the following exercises:
1. Create an application that uses FocusListener to make sure that a text field's value
is multiplied by -1 and redisplayed any time a user changes it to a negative value.
2. Create a calculator that adds or subtracts the contents of two text fields whenever
the appropriate button is clicked, displaying the result as a label.
Where applicable, exercise solutions are offered on the topic's website at http://www.
java21days.com.
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