CIS 644 Aug. 25, 1999 tour of Java

First … about the media lectures… we are experimenting with the media format please give feedback

... not (much) programming in Java. We will write and compile Java declarations (framework) for some sample problems. TogetherJ design tool generates Java frameworks.

Classes objects methods class / instance variables constructors observers (“get”) generators (“set”) mutators inheritance (single) signature interface

Software architecture: applications applets servlets beans

file named HelloWorldApp.java /** * The HelloWorldApp class implements an application that * simply displays "Hello World!" to the standard output. */ class HelloWorldApp { public static void main(String[ ] args) { System.out.println("Hello World!"); //out the string. }

Import class extend implements { } c_modifiers: final abstract public

Method / variable modifiers abstract static native final synchronized public private protected

Objects: 1. declaration: 2. instantiation: new 3. initialization: 4*. Use… reference (observers), update (mutators) n1. Finalize n2. garbage collection

Interface extends package synchronized try catch ( )

JavaTM Platform Core API Specification package java.applet package java.awt package java.awt.event package java.awt.image package java.beans package java.io package java.lang package java.math package java.net package java.rmi package java.text package java.util package java.util.zip …. And more

Systems/Info/JDK1.2/index.html

Collections Implementations: Hash Table, Resizable Array, Balanced Tree, Linked List Interfaces: Set … as HashSet, TreeSet List … as ArrayList, LinkedList Map … as HashMap, TreeMap

Communication: parameters, return parameter event … isa parameter Listener classes and interfaces, methods as: public void mosePressed( MouseEvent e) adapter class exception …. implicit parameter Threads …. Runnable interface

Storage and deployment: *.java …. Source file *.class …. Compiled (byte codes) *.jar ………. Archive (zipped) Beans … reusable component, with standard bean interface, …. COM wrapper classes

End