====== Week 2 ======

~~NOTOC~~




===== Introduction / Science of Abstraction =====

  * Office hours: posted! 

  * (continued from slide 8)
    * Lecture notes: {{courses:cs203-201301:203-introduction.pdf|203-introduction.pdf}} \\ \\
    


===== Understanding Objects in Java ===== 


**Origins of Java (sidebar 2.1)** ((Liskov p. 16))
  * Java is a successor to Scheme and SmallTalk (among other languages).
  * Java is only superficially (syntactically) similar to C and C++. Semantically, Java is very different from these and other languages.

**Packages** ((Sestoft pp. 72-73)) 
  * Java source files may be organized into //packages//. Every source file in package ''p'' must begin with the declaration<code java>
package p;
</code> and must be stored in a subdirectory called ''p''.
  * A class declared in a source file with no ''package'' declaration belongs to the anonymous //default package//. 
  * Our BlueJ projects last year in 102 were all //default package// projects, but the projects we create in Netbeans this semester will all have explicit ''package'' declarations. 
  * Class ''C'' within package ''p'' may be imported explicitly using<code java>import p.C;</code> or all classes within package ''p'' may be imported using wildcard notation: <code java>import p.*;</code>
  * Let's take a look at named and default packages in Netbeans.

**Objects and Variables** ((Liskov Section 2.3))
  * Stack and Heap diagrams figure 2.2 (p. 19)
  * Exercises 2.1, 2.2, 2.3, 2.4
    * //Exercises 2.1, 2.2, and 2.3 are HW for next Monday's class/