Mastering Java: The Ultimate Quiz for 'Thinking in Java'

The Swing GUI components are not available in the java.awt package, as this package contains more basic AWT components. The java.gui package does not exist, so C is not the correct answer. Lastly, the Java Components Library is not a valid package, so D is not the correct answer. Therefore, option B, javax.swing, is the correct answer as it is the designated package for Swing GUI components in Java.