Java Web Programming Training

INHERITANCE AND POLYMORPHISM:
Abstract Classes: may contain method implementations and unimplemented method definitions. A class can only extend one abstract class.
A valid example of inheritance is:
.Animated is a class
|Human extends animated
||Individual extends Human
|||Employee Extends Individual

Facts:
* Employee cannot extend Human and Manager at the same time
* At Employe is an Individual and Human and Animated.

Interfaces: Contains only method definitions and constants. A class can implement more than one interface.

METHODS:
* Primitive types (lower case type [8 primitive types]) when used as parameters generate a new variable with a scope local to the invoked method.
* Objects when used as parameters are references to the original class in the invoking method, thus, any operations on the parameter variable are actually being executed in the original object. This behavior does not hold across serialized and deserialized instances of an object, use RMI to keep the references across virtual machines and applications.

SERIALIZATION:
* TRANSIENT means that the code in methods is not stored along with the data, it is a good security measure to protect business rules and special algorithms.
* RECURSIVE (recursively) serializes the object type members of a class.
* VERSIONING: http://www.javaworld.com/javaworld/jw-03-1998/jw-03-beans-p2.html
* STATIC VARIABLES are never serialized.

JSP:
* When first run a jsp page the tomcat environment generates a .java file and compiles it as a Servlet.

* TOMCAT: Configuration at server and app level
* CLASSLOADER: A class that loads the libraries referenced in the import clause, it has a predefined search order: bootstrap, %JAVA_HOME%/common/lib; webapps/AppName/WEB-INF/lib/*.jar

SOFTWARE:
Jdk 1.4.0.2_05
NetBeans 3.6
Jboss 4.0.03sp1
Tomcat 5.0.28
Ant 1.6.2
Hypersonic

Installation:

• create a %home% user variable for each product (java, jboss, hypersonic, tomcat, etc.)
• That considerably eases and shortens your PATH variable (also user)
  

FILE TYPES:

• WAR Web Archives
• JAR Java Archive
• EAP
  

WEB APP FOLDER STRUCTURE:

• META-INF: App generated metadata
  
• WEB-INF: Has the web.xml file and the classes folder where servlet classes reside
• WEB-INF/web.xml: contains the servlet to class mappings.

EVOLUTION:
oak => java 1.0 (poc) => java 1.1 => java2 1.2

REFERENCE:
* (Sun) The J2EETrademarked 1.4 Tutorial: http://java.sun.com/j2ee/1.4/docs/tutorial/doc/
* (Sun) Java 1.4 API Specification (javadoc): http://java.sun.com/j2ee/1.4/docs/api/
* (Oracle) Web Services Tutorial: http://www.oracle.com/technology/tech/webservices/htdocs/series/index.html