During the first week, you learned about the core elements of the Java language: objects; classes; interfaces; and the keywords, statements, expressions, and operators that they contain.
For the second week, the focus shifts from the classes you create to the ones that have been created for you: the Java class library, a set of standard packages from Sun Microsystems with more than 1,000 classes you can use in your own Java programs.
Today, you start with classes that represent data.
The Java class library provides a set of data structures in the
java.util package that gives you more flexibility in organizing and manipulating data.
A solid understanding of data structures and when to employ them will ...