About Java and This Class

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About Java and This Class

• Written by Jeff Smith
• Portions Borrowed From Publicly Available
  Information

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One NOAA -1

• In 2002, the NOAA Program Review Team (PRT)
  concluded NOAA was not adequately structured to
  meet its current and future missions efficiently
  and effectively. 
• The PRT determined NOAA would be better served
  by moving from the existing Line Office structure
  to a more integrated structure, one that reflects
  the interdisciplinary and multidisciplinary
  nature of the challenges facing society.
• ESRL was formed

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One NOAA -2

• Our laptops wont connect to any network disk
  location, making it difficult to share files
• So in the spirit of One NOAA, I have created One
  yahoo email account we can use to send files to
  each other
• name corejava101_at_yahoo.com
• password onenoaa
• I will use it to send you my solutions to
  exercises we work on in class
• One NOAA, one ESRL, one email account for all of
  us

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What is Java -1

• Javas Origins
• Originally codenamed Oak, the Java language was
  created and released by Sun Microsystems in 1995.
  
• The Java compiler creates one standard binary
  (bytecode) format for all operating systems. Thus
  you can compile your Java code on a PC and run it
  on a Linux machine or a Mac. This works because
  the Java bytecode runs in a Java Virtual Machine
  (JVM) or interpreter on each platform.
• Thus as new operating systems (OS) are developed,
  someone creates a JVM for it and your code will
  then run on the new OS!

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What is Java -2
Java Development Kit (JDK) Major Milestones JDK
1.0 Summer 1995 JDK 1.02 Jan 1996 JDK 1.1
Feb 1997 (Jeff Smith begins using Java!) JDK
1.2 Jan 1998 (major improvements to JDK)
(this version is commonly referred to as Java
2) JDK 1.3 May 2000 JDK 1.4 Dec 2001 JDK 1.5
Sept 2004 JDK 1.6 (code name
Mustang, released later in 2006)
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What is Java -3
Versions of Java J2EE - Java 2 Enterprise
Edition Contains all standard libraries, plus
serverside Java--includes servlets, EJBs
(enterprise Java beans), CMT, JMS, etc. Commonly
used for web applications and distributed
systems. J2SE - Java 2 Standard Edition Standard
version of Java with all standard libraries.
Commonly used for applications and applets that
run on a single machine. J2ME - Java 2 Micro
Edition Small footprint--stripped down version of
Java that will run on machines (like cell phones)
without much memory.
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What is Java -4
Java and Javascript Javascript is NOT a light
version of Java. It is a client side (e.g.
browser) scripting language which superficially
looks like Java. It is very useful for web page
development, but should not be confused with the
Java language. Netscape made a great marketing
decision in naming it Javascript so they could
capitalize on the popularity of Java.
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What is Java -5

• Execution Environments
• Applications - standalone program which has a
  main() method (so it can run on its own).
• Applets - Program that runs from within a browser
  or applet viewer
• Servlets - Run in a J2EE container (like Tomcat)
  in a web server. JSPs (Java Server Pages) are
  special kinds of servlets.
• EJBs - Heavyweight Java components that run in a
  J2EE container or application server (like JBoss)

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What is Java -7
What is Swing and JFC? Swing is one application
programming interface (API) out of the four API's
in the Java Foundation Classes (JFC).  JFC
contains the Swing API, the Accessibility API,
Drag and Drop support, and the Java2D API.
Swing provides a robust set of graphical user
interface (GUI) components that are platform
independent, and have a consistent look and feel
across all platforms. Swing provides improvements
over the old Abstract Windowing Toolkit (AWT), a
previous generation GUI API for Java.
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What is Java -8
What is SWT (Standard Widget Toolkit)? SWT is a
new GUI library that is a potential alternative
to Swing. IBM is a big advocate of SWT. SWT
delivers native widget functionality for the
Eclipse platform in an operating system
independent manner. It is analogous to AWT/Swing
in Java with a difference - SWT uses a rich set
of native widgets. It access these native GUI
features (e.g. Windows API) via the standard Java
Native Interface (JNI). The main drawback is
that it is not universally supported (like
Swing). It does work in Windows, Linux, and
Solaris however.
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What is Java -9
What is JBoss? JBoss is an open source developed
application server for J2EE applications (your
Java code runs within the JBoss environment).
At the present time, JBoss has the largest
market share, ahead of BEA Weblogic and IBMs
Websphere. Known for its ease of use, modularity
and simplicity, JBoss is a powerful (and free)
J2EE-based server. Apache Geronimo is also open
source as is trying to overtake Jboss.
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What is Java -10
What is Ant? Jakarta Ant is the defacto standard
tool for compiling Java projects and it is free.
It can be invoked from the command line or
integrated into an IDE like Eclipse. You can
think of it as an improved version of the make
utility. Currently, we are using Ant 1.51. To
use Ant, typically you create a build.xml file
which lists the files you want compiled and into
which directories. When you launch Ant, it reads
this file and compiles the project
accordingly. Ant is a powerful and fairly easy
to use tool which can used to automate a variety
of scripting tasks. You can learn more
at http//ant.apache.org/index.html
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What is Java -11
What is Struts? Struts is a framework for
organizing and creating Servlet based websites.
For example, if we rewrote WMS as a web
application, we would use Struts. Struts is part
of the Apache Jakarta Project (open source and
free) and is rapidly becoming a standard for Java
based web development. Struts employs a
variation of the classic Model-View-Controller
(MVC) design pattern (something we will cover
later).
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What is Java -12
What is JUnit? JUnit is an open source (free!)
regression testing framework used for conducting
unit tests in Java. It is a fairly standard
tool. Typically, a Java developer creates JUnit
test cases while developing code (some developers
even do it before they write the code). With the
test cases written, a developer can easily run
the regression tests each night before checking
in any code (to verify that new bugs have not
been introduced). You can learn more about it at
www.JUnit.org
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What is Java -13
A Word About Buzzwords There are many Java
related buzzwords and fancy design patterns
(particularly in the J2EE world). Dont be
intimidated by this! The goal of program
development is to write clear and concise code
which is easy for other programmers to use,
extend, and maintain. If you achieve this, you
are a good Java developer, regardless of whether
you know every buzzword or can list 150 design
patterns off the top of your head. That said, it
never hurts to see what design patterns (coding
strategies) are working for other people. Other
people occasionally come up with clever solutions
to problems!
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Why Java? -1

• Runs on most operating systems without
  recompiling
• Future-proofs your code (your Java code will run
  on future Microsoft 64 bit operating systems)
• Program everything from servers to handheld
  computers (with J2ME)
• Similar syntax to C makes it easier for C
  programmers to learn
• Simpler and cleaner code than C
• Networking is built into Java, making it easy to
  write socket daemons and utilities in Java

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Why Java? -2

• True object oriented language, maximizing code
  reuse (through inheritance) and minimizing
  development and maintenance time
• Enormous code base (libraries) exists to assist
  in the implementation of complex future projects
• Lots of Java developers available to hire
• Free development tools (JDK, Eclipse, Sun ONE
  Studio)
• Internationalization The Unicode character set
  is an integral part of Java, making it easier to
  support warehouses in non-English speaking
  countries if WMS needs to be used in new markets.
  

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Why Java? -3

• Why Java? Java is Error Resistant
• Java puts a lot of emphasis on early checking for
  possible errors, as Java compilers are able to
  detect many problems that would first show up
  during execution time in other languages.
• Java eliminates certain types of programming
  constructs in other languages that are prone to
  errors. For example, there is no pointer
  arithmetic that can go awry.
• Java automatically frees objects you create,
  using its garbage collector (no more memory
  leaks!).

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Why Java? -4

• Why Java? -- Good Multithreading Support
• In Java, multithreaded programming has been
  smoothly integrated into it, while in other
  languages, operating system-specific procedures
  have to be called in order to enable
  multithreading.
• Multithreading is especially useful in graphical
  user interface (GUI), network, and db
  programming. In db programming multiple threads
  can execute queries simultaneously (very useful
  on a multi-processor db server, like the servers
  we have in each warehouse).

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Why Not Java? -1

• There is a performance penalty for using bytecode
  instead of natively compiled applications. Early
  Java virtual machines (JVM) ran code very slowly
  compared to C/C/Delphi. Current JVMs are much
  faster, probably on the order of 20 slower than
  native code. In most real world applications,
  this is negligible since most of the processing
  time is spent in database access or waiting for
  user input.
• Java isnt suited for low level device
  programming (like video drivers) which require
  maximum speed and direct access to the hardware.
  C/C/Delphi/Assembler are better suited for
  those tasks.
• You want to write relatively simple code to
  perform OS related programming (hence a UNIX
  shell script, DOS command script, or Ant script
  might be easier).

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Just Java 2 Book -1

• Just Java 2 by Peter van der Linden
• This is a good introduction to Java
• Core Java syntax and structure
• OOP concepts
• Threads
• File I/O
• Collections, Lists, etc.
• Networking
• Servlets and JSP
• Applets and Swing
• Security
• JDBC (Java database connectivity)
• XML

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Class Time / Structure
Ill strive to divide our classes up with 50 of
our time looking and talking about slides and 50
of our time actually writing Java programs on the
classroom computers. Our laptops have 1GB of
RAM, so they should be good for running IDEs,
Tomcat, etc.
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Java on the Web -1

• Suns Java Tutorial Pages
• http//java.sun.com/docs/books/tutorial/
• IBMs Java Technology Zone (Developer Works)
• http//www-106.ibm.com/developerworks/java/
• TheServerSide.com (J2EE Community)
• http//www.TheServerSide.com
• Latest Java news, great interviews and threads on
  a number of different Java related technologies.
  Authors of several J2EE books add their two cents
  to many threads
• Find out some of the things about Java and J2EE
  that you wont find on the official Sun
  website.
• Java Lobby (Community) at http//www.javalobby.org
  /

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Java on the Web -2
Java on the Web -1
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Java Development at GSD -1

• WRF Portal Swing application front end for
  running WRFhttp//www.wrfportal.org
• Domain Wizard Swing application front end for
  creating domains and running the WRF
  preprocessor http//www.wrfportal.org/DomainWizar
  d.html
• RTVS rewrite Nick, Missy and Dan are developing
  the next generation of RTVS in Java
• AWIPS Raytheon is rewriting AWIPS using an
  enterprise Java architecture
• STMAS viewer-AWT applet by Bill
  Moningerhttp//www-frd.fsl.noaa.gov/stmas/view
• FX/Net Swing application, Evan and Jebb

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Questions For You

• What is your background with computers,
  programming, and Java?
• What do you plan to do in Java in the future?

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A Final Word -1

• Learning Java and OOP
• Learning OOP will be an ongoing process
• For most people, it takes multiple exposures to
  OOP literature and instruction to get it. So
  dont get discouraged if it takes a while! That
  is normal.
• OOP is pretty standard stuff. The terminology,
  concepts, and even the syntax are similar among
  Java, C, C, Object Pascal (Delphi), Python,
  and other OOP languages.
• The OOP and OOD (object oriented development)
  concepts you learn for Java will serve you well
  with other OOP languages too.