... charAt takes an index andreturns the character at that index. indexOf takes a character and finds theindex where that character appears.charAt fails if the index is out of range, and causes an ... them.8.2 PackagesThe built-in Java classes are divided into a number of packages, includingjava.lang, which contains almost all of the classes we have seen so far, andjava.awt, which contains classes ... Glossarypackage: A collection of classes. The built-in Java classes are organized inpackages.AWT: The Abstract Window Toolkit, one of the biggest and most commonly-used Java packages.instance:...