Java on net

Service Wrapper for Java

2011-11-30T23:20:00.001-06:00

From Wikipedia (http://en.wikipedia.org/wiki/Service_wrapper) (Nov 30, 2011)
A service wrapper is a computer program that wraps arbitrary programs thus enabling them to be installed and run as Windows Services or Unix Daemons, programs that run in the background, rather than under the direct control of a user. They are often automatically started at boot time. Arbitrary programs cannot run as services or daemons, unless they fulfill specific requirements which depend on the operating system. They also have to be installed in order for the operating system to identify them as such.
Examples:
* Apache Daemon (http://commons.apache.org/daemon/)
* Launch4j (http://launch4j.sourceforge.net/)
* Java Service Wrapper (http://wrapper.tanukisoftware.com/doc/english/introduction.html)
* YAJSW (http://yajsw.sourceforge.net/)

Service component architecture (SCA)

2010-06-28T13:55:00.004-05:00

Service Component Architecture (SCA) is emerging standard which aims to provide a model for the creation of service components in a wide range of languages and a model for assembling service components into a business solution [1].

The SCA specification is divided into a number of documents, each dealing with a different aspect of SCA [4]. Like, the Assembly Model describes wiring components. The Assembly Model is independent of implementation. The Client and Implementation specification deals with the implementation of services and of service clients -- SCA has published specifications for BPEL, C++, Spring and Java component implementation specifications.

List of current SCA specification can be found at OSOA's website at - http://www.osoa.org/display/Main/Service+Component+Architecture+Specifications. Most of the specifications published in 2007. I am still trying to figure out what is the current status of SCA.

References:

[1] Service Component Architecture (SCA) (http://www.oasis-opencsa.org/sca)

[2] What is Service Component Architecture? Is it an alternative to SOA or is it an addition? (http://blog.softwareag.com/index.php/2008/06/10/what-is-service-component-architecture-is-it-an-alternative-to-soa-or-is-it-an-addition/)

[3] Service component architecture - Wikipedia Page (http://en.wikipedia.org/wiki/Service_component_architecture)

[4] Service Component Architecture (http://www.ibm.com/developerworks/library/specification/ws-sca/)

[5] Service Component Architecture Specifications (http://www.osoa.org/display/Main/Service+Component+Architecture+Specifications)

5 thing about Jars - From IBM Developerworks

2010-06-25T10:55:00.002-05:00

From IBM Developerworks - 5 things you didn't know about ... JARs

1. JARs are executable: Manifest file can be modified to specify which class to launch when executing JAR. User then just have to execute JAR, at command line or simply by double clicking it.

2. JARs can include dependency information: Manifest allows declaration of JAR dependencies using "Class-path" attribute. This implicitly creates the CLASSPATH without having to declare it.

3. JARs can be implicitly referenced: Use "extension directory", the lib/ext directory, underneath JRE location.

4. Java 6 allows classpath wildcards

5. JARs hold more than code: For example, configuration files like Hibernate mappings.

Inspiring talk from Kathy Sierra

2010-06-25T01:20:00.002-05:00

Another inspiring talk from Kathy Sierra

Thanks to blog - Frank Carver's Punch Barrel

Follow her secret answer. Pretty interesting views and so inspiring.

Powered by ScribeFire.

Auto Tweet on Twitter Using Java @PCQuest

2009-08-30T18:08:00.002-05:00

Article: Auto Tweet on Twitter Using Java
Author: Rahul Sah
Link: http://pcquest.ciol.com/content/Developer/2009/109070401.asp
Summary:
Twitter4J is a Java library for Twitter API. It is completely implemented in Java and spares you the hassles of creating your own wrapper for Twitter APIs for your Java application to access Twitter. This article shows how you can it be used to access Twitter through a Servlet Web application.

Additional Link: Twitter4J (http://yusuke.homeip.net/twitter4j/en/index.html)

How to Use Spring Web Service @JavaLobby

2009-08-29T03:47:00.001-05:00

A How-To article (http://java.dzone.com/articles/spring-ws-how) to expose a simple web service using Spring Web Services at JAVALOBBY (http://java.dzone.com) - author Biju Kunjummen.

Spring source bought by VMware

2009-08-10T23:28:00.002-05:00

Two companies or rather movements I have come to admire, are coming together. Spring source have been bought up by VMware.

See link: VMware to Buy SpringSource for $420M at Gigaom.com

Article on REST WebServices

2008-11-10T11:25:00.003-06:00

Jeremy Deane of Collaborative Consuluting has two part article "RESTful Web Services: Development and Testing
" published at bpminstitute.org. Article covers introduction of REST Web Services and explains development of an example using Restlet framework. Few points from that article -

REST (Represntational State Transfer)
* Simpler than SOAP, has less steps than SOAP development.
* Provides access to resources identified by URI using HTTP.
* Resources are abstraction of information
* Supports HTTP operations - GET, PUT, POST and DELETE (analogous to CRUD)
* Each interacion updates the state (except GET).
* Interactions are idempotent
* Security is provided by authentication, authorization and auditing

Design considerations
* What are the entities (resources)?
* What are the resource representations formats?
* How are entities related to each others (links)?
* What ids resources (ids should be descriptive and scalable)?
* How to use HTTP status code? (Should avoid for lose coupling between provider and consumer)

Important classes of Restlet framework
* Converter
* Router
* Resource
* Guard

Java WebServices Standards

2008-11-03T17:56:00.003-06:00

Java Standards related to WebServices (Note: not in any particular order)

1. Java API for XML Web Services (JAX-WS) [JSR 224]
2. Java Architecture for XML Binding (JAXB) [JSR 222]
3. WSEE [JSR 109]
4. WS-Metadata [JSR 181]
5. Java Business Integration (JBI) [JSR 208]

Reference:
* SOA Using Java(TM) Web Services by Mark D. Hansen (http://soabook.com/)
* The JAVA EE5 Tutorial (http://java.sun.com/javaee/5/docs/tutorial/doc/)
* Java Standards at SearchSOA.com (http://searchsoa.techtarget.com/topics/0,295493,sid26_tax305810,00.html)

Portlet Specification V2.0 at IBM developerworks

2008-04-08T03:06:00.002-05:00

Detailed article about portlet specification v2.0 at IBM developerworks -
What's new in the Java Portlet Specification V2.0 (JSR 286)?

Proxy setting in Eclipse

2008-02-14T15:37:00.000-06:00

I have been asked again - "Where is the proxy setting in Eclipse?"

In Eclipse 3.3 - Windows -> Preferences -> General -> Network Connections

In Eclipse 3.2 - Windows -> Preferences -> Internet -> Proxy Settings

Reference for JSF, Spring and JPA

2008-02-05T23:57:00.001-06:00

I referred to Carol McDonald's Blog entry -
Sample Application using JSF, Spring 2.0, and Java Persistence APIs (http://weblogs.java.net/blog/caroljmcdonald/archive/2007/06/sample_applicat.html) for reference on JSF, Spring and JPA.

Eclipse Basic Shortcuts

2007-08-20T00:26:00.000-05:00

Eclipse comes with basic tutorial and it could also be found online at -

http://help.eclipse.org/help33/index.jsp?topic=/org.eclipse.jdt.doc.user/gettingStarted/qs-BasicTutorial.htm

Outlining few shortcuts for the some features explained there -

* Navigate Outline (Ctrl+O) 2 times for inherited items

* Content Assist (Ctrl+Space)

* Run As (Alt+Shift+X) Java Application +J

* Show line numbers -> Windows->Preferences->General->TextEditors

* Source > Organize Imports (Ctrl+Shift+O)

* Restore from local history

* Refactor (Alt+Shit+T)

* Creation and configuration of generated comments in the Java > Code Style > Code Templates preference page.

* Source (Alt+Shift+S) ->
+v: Override/Implement methods
+r: Generate Getters and Setters

* View declaration (Ctrl+G)

* View Type Hierarchy (Ctrl+T) or Navigate > Quick Type Hierarchy
Ctrl+T to toggle between supertype hierarchy and subtype hierarchy.

* Evaluating snippets: New > Other > Java > Java Run/Debug > Scrapbook Page

Integration Pattern

2007-08-15T10:52:00.001-05:00

Integration is an essential part of most of the enterprise systems now a days. Here is a quick guide for enterprise integration patterns, nicely explained with diagrams :

Enterprise Integration Patterns - Table of Contents (http://www.enterpriseintegrationpatterns.com/toc.html)

This is Table of Contents for the book - Enterprise Integration Patterns (http://www.enterpriseintegrationpatterns.com/index.html) which explains each of
patterns in detail. A sample chapter of the book can be downloaded from:
http://www.enterpriseintegrationpatterns.com/docs/EnterpriseIntegrationPatterns_HohpeWoolf_ch03.pdf

Decoupling user and creator in Factory Pattern

2007-07-06T13:21:00.000-05:00

It is a good idea to decouple user and creator in factory pattern. This technique is also mentioned as Simple Factory Pattern/Idiom.

Following is diagram from "Manufacturing Java Objects with the Factory Method Design Pattern by Barry Burd and Michael P. Redlich" (http://javaboutique.internet.com/tutorials/factory/) explaining basic factory pattern.

Here, Creator is also user of the Product. This creation and use is tightly coupled.

A "SimpleProductFactory" element can be added to Creator class (composition), which would be responsible of creating Product. Thus, decoupling use and creation of the Product.

Links:-

* Sun Developer Forums: Problem understanding Factory Method Pattern
* Manufacturing Java Objects with the Factory Method Design Pattern by Barry Burd and Michael P. Redlich (http://javaboutique.internet.com/tutorials/factory/)

JUNIT 4 Tutorial on IBM Developerworks

2007-06-15T01:01:00.001-05:00

Look at Jump into JUnit 4 by Andrew Glover, for introduction on JUnit 4.
JUnit 4 is complete makeover of JUnit with excellent use of annotations. Working with test cases has been made easier by relaxing stringent requirements of earlier versions.
Tutorial covers fundamental concepts, new features along with examples.
Article do points that "Many argue that JUnit 4's use of annotations was influenced by TestNG as well as .NET's NUnit."

Other resources:

1. Junit offical website (http://www.junit.org/index.htm)
2. Junit 4.3 JavaDoc (http://www.junit.org/junit/javadoc/4.3/index.htm)
3. JUnit Reloaded by Ralf Stuckert on java.net (http://today.java.net/pub/a/today/2006/12/07/junit-reloaded.html)

Java: Static methods are not overriden

2007-03-23T10:20:00.000-05:00

In Java, sub-class static method can have same signature as super-class static method. But it does not mean that super-class static method is overridden by sub-class static method. Look at the following code (from reference)
-------------------------------------------
/*

* SubClass.java

* Created on den 23 juni 2005, 21:13

package sample;

/**

* @author Thomas

public class SubClass extends SuperClass{

public static Long getStaticLongId(){

return 2L;

}

public Long getInstanceLongId(){

return 20L;

}

public static final void main(String args[]){

SubClass subClassInstance = new SubClass();

System.out.println("Static overloading:\t" +

SubClass.getStaticLongId() + "\t" +

SubClass.getStaticStringId());

System.out.println("Instance overloading:\t"+

subClassInstance.getInstanceLongId() + "\t" +

subClassInstance.getInstanceStringId());

}

* SuperClass.java

* Created on den 23 juni 2005, 21:09

package sample;

/**

* @author Thomas

public class SuperClass {

public static Long getStaticLongId(){

return 1L;

}

public static String getStaticStringId(){

return getStaticLongId().toString();

}

public Long getInstanceLongId(){

return 10L;

}

public String getInstanceStringId(){

return getInstanceLongId().toString();

}
}
------------------------------------------------------

Output will be -
Static overloading: 2 1
Instance overloading: 20 20

For detailed reason about it, look at the reference.

As a side-note, if you put this code in eclipse, you will see little triangle by the side of overridden instance method "getInstanceLongId()". This sign will be missing for static method "getStaticLongId()".

Reference:
* Overriding static methods - why doesn´t it work?

TSS Article on SOA

2007-03-15T01:28:00.001-05:00

Article ESB, Service Implementation and the Return of the EJB on TheServerSide by Frank Teti, tells about SOA in general. Good to read, to know what different options you have in SOA.

It has also a mention about MULE (http://www.mulesource.com/), this open-source ESB solution has recently crossed 500K download mark (http://www.mulesource.com/company/press_releases/500K_011707.php).

Eclipse to test WSDL

2006-08-11T11:22:00.000-05:00

With Eclipse you can test WSDL without writting code.
Link: http://help.eclipse.org/help32/topic/org.eclipse.jst.ws.consumption.ui.doc.user/tasks/ttestwsdl.html

Annotations in Java 1.5

2006-08-11T00:41:00.000-05:00

Annotations are metadata used in source code to be interpreted by the tools and libraries without affecting the execution of the program. Annotations can be interpreted at compile-time or run-time. A use of annotation could be, mark a method as deprecated; use of deprecated can then be interpreted by the compiler to generate warnings. Another use could be pass configuration values for the tool to be process, generate or modify configuration files. Annotations are beneficial in documentation, code-analysis and compiler checking.

Example:
@deprecated public void foo(){}

Annotations consist of '@' sign followed by type of annotation and a parenthesized list of name-value pair of elements. Annotations can be used everywhere where other modifiers like public or static can be used. As a convention annotation is preceded by other modifiers.

Declaration of annotation type:
Example: public @interface breaksStandard {
public String reviewer();
public String reviewDate;
public String reason default "";}

Similar to interface declaration, modifier '@' sign prefixed to keyword interface. Return types can only be primitives, String, Class, enums and annotations (and arrays of these).

Usage: @breaksStandard(reviewer="XYZ", reviewDate="Aug 10, 2006") public void FOO(){}

Types:
1. In built annotations -
i. The Override annotation
ii. The Deprecated annotation
iii. The SuppressWarnings annotation

2. User Defined annotations

Categories:
1. Marker annotations
2. Single-value annotations
3. Full annotations

Meta-Annotation:
Annotations of annotations are meta-annotation. e.g. @Target, @Retention, @Documented.

Exercise: Work with @Deprecated or @Override annotation in Eclipse.

References:

[1] http://java.sun.com/j2se/1.5.0/docs/guide/language/annotations.html Annotations
[2] http://www-128.ibm.com/developerworks/java/library/j-annotate1/ , Annotations in Tiger, Part 1: Add metadata to Java code, Author: Brett McLaughlin
[3] http://www-128.ibm.com/developerworks/java/library/j-annotate2.htm l, Annotations in Tiger, Part 2: Custom annotations, Author: Brett McLaughlin
[4] http://www.infoq.com/articles/Annotation-Hammer Annotation Hammer, Author: Venkat Subramaniam
[5] http://www.javaworld.com/javaworld/jw-03-2005/jw-0321-toolbox.html An annotation-based persistence framework, Author:Allen Holub

Controversy controversy controversy

2006-07-14T11:25:00.000-05:00

Its every where I see. So many links that I lost count. Can you guess what is IT??

* Richard Monson-Haefel: It's too late to save Java EE (http://www.infoq.com/news/Java-EE-Demise-Report)
* Is Java EE's Complexity Its Worst Enemy?(http://www.internetnews.com/dev-news/article.php/3618166)
* The Beginning of the End for Java Starts(Date.Time.NOW()); (http://www.oreillynet.com/windows/blog/2006/07/the_beginning_of_the_end_for_j.html)
* Analysts see Java EE dying in an SOA world (http://searchwebservices.techtarget.com/originalContent/0,289142,sid26_gci1198211,00.html)
* Analysts see Java EE dying in an SOA world (http://www.theserverside.com/news/thread.tss?thread_id=41283)

Controversies are good sometime. Personally I don't believe that JEE dying. My 2 cents, 'May the best one win'. People!! you have much choices now then say couple of years back. Evaluate and find which one fits best to you. May you choose JEE over others. Complexities will be there with all the Enterprise level projects. There are lot other factors to consider. Resources involved, total cost of ownership, return of investment, maintainability etc etc.

Links for eclipse 3.2 Callisto

2006-07-05T14:53:00.000-05:00

Will add more soon
1. Eclipse Callisto http://www.eclipse.org/callisto/
2.
What's New in Eclipse 3.2 Java Development Tools http://www.onjava.com/pub/a/onjava/2006/06/28/whats-new-in-eclipse-3-2-java-development-tools.html?page=3
3. Ten coolest Eclipse 3.2 features http://blogs.zdnet.com/Burnette/?p=136
4. Customize Your Callisto Experience http://www.eclipse.org/callisto/custom.php
5. Eclipse Updates 10 Open-Source Projects in 'Callisto' http://www.eweek.com/article2/0,1895,1981651,00.asp
6. Step-by-step Eclipse Callisto http://www.ebernie.net/blog/2006/06/21/step-by-step-eclipse-callisto/

-----------------------------------------------------
New:
7. Series of Callisto podcasts http://www.eclipsezone.com/spotlights.jsp
-----------------------------------------------------

Trivia:
* Release Date: June 30, 2006
* Callisto, named for a moon of Jupiter
* The 10 projects included in the Callisto release are:
1. Business Intelligence and Reporting Tools (BIRT) 2.1
2. C/C++ IDE (CDT) 3.1
3. Data Tools Platform (DTP) 1.0
4. Graphical Editor Framework (GEF) 3.2
5. Graphical Modeling Framework (GMF)1.0
6. Eclipse Project 3.2
7. Test and Performance Tools Platform (TPTP) 4.2
8. Web Tools Platform (WTP) 1.5
9. Visual Editor (VE) 1.2
10. Eclipse Modeling Framework (EMF) 2.2

Links for JUnit on Eclipse

2006-06-06T11:36:00.000-05:00

List of links for JUnit on Eclipse. Looking forward for more additions.

1. Unit Testing in Eclipse Using JUnit (http://open.ncsu.edu/se/tutorials/junit/#section6_0)
Date: Aug 29, 2005
To the point tutorial.

2. Using JUnit in Eclipse (www.cs.umanitoba.ca/~eclipse/10-JUnit.pdf)
Date: Oct 30, 2003
With a quick example

3. Eclipse Junit testing tutorial (http://www.laliluna.de/eclipse-junit-testing-tutorial.html)
Date: April, 12 2005
Definations, examples and source code

Quick reference of Autoboxing in JDK 1.5

2006-06-02T15:11:00.000-05:00

Boxing is simply converting primitive type to wrapper class. e.g. Integer intObj = new Integer(100). Autoboxing is compiler taking care of boxing. WIth autoboxing following is a legal statement:
Integer intObj=100;

Vice-versa is called unboxing. JDK 1.5 supports autoboxing and auto-unboxing.

Following is legal with autoboxing
1. Integer intObj1=100; Integer intObj2=200;
2. Integer intObj3=intObj1+intObj2;
3. map.put("zero", 0); //map is defined as Map
4. int z=map.get("zero");
5. Boolean result= (intObj1==intObj2);
6. int intValue = intObj1; //throws nullPointerException
7. foo(intValue); //foo is defined as - public void foo(Integer intObj1){}
8. bar(intObj1); //bar is defined as - public void bar(int intValue){}
9. if(booleanObj){} //booleanObj is of type Boolean
10. int intValue = -intObj1;

Following is illegal
1. Integer intObj=shortVal; // shortVal is of type short
2. Double doubleObj = 10; //Can not convert from int to Double

Advantage of autoboxing and auto-unboxing is concise code. But careless use might result in poor performance of the code. Certain primitives are cached and autoboxing returns same wrapper objects. This value may depend on jvm used, normally this value are:
1. The boolean values true and false.
2. The byte values.
3. The short and int values between -128 and 127.
4. The char values in the range '\u0000' to '\u007F'.

It means, if intObj1=127 and intObj2=127 then intObj1==intObj2 returns true. But, if if intObj1=128 and intObj2=128 then intObj1==intObj2 returns false.

Best practices compiled by Brian Pontarelli at http://brian.pontarelli.com/2004/07/15/jdk-5-auto-boxing-best-practices [3]

If you can use primitives do it, if you can’t don’t.
1. Avoid using wrapper classes whenever possible.
2. Never do math with wrappers.
3. Try not to use any of the comparison operators (<, >, <=, >=, ==, etc) with wrappers.
4. Avoid usage in loop statements.
5. Always check for null values.

References:

[1] SCJP 5 : Chapter 3. API Contents (Part-1) http://www.exforsys.com/content/view/1885/362/
[2] Autoboxing surprises from J2SE 5 http://www.theserverside.com/news/thread.tss?thread_id=27129
[3] JDK 5 - auto-boxing best practices http://brian.pontarelli.com/2004/07/15/jdk-5-auto-boxing-best-practices/
[4] J2SE 5.0 in a Nutshell http://java.sun.com/developer/technicalArticles/releases/j2se15/
[5] Autoboxing http://java.sun.com/j2se/1.5.0/docs/guide/language/autoboxing.html
[6] Object type http://en.wikipedia.org/wiki/Autoboxing

TheServerSide @ JavaOne 2006

2006-06-01T16:30:00.000-05:00

Enterprise Java Community: TheServerSide @ JavaOne 2006

Above link is TheServerSide report on JavaOne2006 By Nitin Bharti, Frank Cohen and Rich Seeley.

Two Java Thread Models

2006-05-25T15:14:00.000-05:00

Java Thread Models; at this webpage Dr. Robert Kline discussed two Java Thread Models.

Model 1. Thread created from the same base
Model 2. Thread with separate bases sharing an object.

While at that page, check out his comparison of C++ and Java at http://www.cs.wcupa.edu/~rkline/cppjava.html.

"It's not a question of whether, but a question of how,"

2006-05-17T00:55:00.000-05:00

Information Week article "Sun's Pledge To Make Java Open Source Leaves Key Questions Unanswered"
states "Sun hasn't said who will manage the code or when it will become open source. "

Read more reactions at eWeek Article: "Sun's Open-Source Outreach Met with Mixed Emotions"

So, will open-source Java mean a lot of different flavors of Java? Will it mean a personalize lean JVM for me? Will it mean I can replace core libraries? May be I will have choice of different Garbage Collector. Well! choice will be endless.

Parsing with StAX in JDK 6.0 - Tutorial and other links

2006-04-14T17:20:00.000-05:00

Parsing with StAX in JDK 6.0: by Deepak Vohra, published at JavaBoutique, is a tutorial about Streaming API for XML (StAX) in Java6.0. StAX is a streaming, pull-parsing API for XML., is a new feature in JDK 6.0.

From this tutorial - " A push model parser generates events until the XML document is completely parsed. But pull parsing is regulated by the application—so parse events are generated by the application. This means with StaX, you can suspend parsing, skip elements while parsing, and parse multiple documents. With the DOM API, you end up parsing the complete XML document into a DOM structure, thus reducing parsing efficiency. With StAX, parsing events get generated as the XML document gets parsed. "

Another link:

Chapter 3: Streaming API for XML of Sun Java Web Service Tutorial

From this link:

XML Parser API Feature Summary
Feature	StAX	SAX	DOM	TrAX
API Type	Pull, streaming	Push, streaming	In memory tree	XSLT Rule
Ease of Use	High	Medium	High	Medium
XPath Capability	No	No	Yes	Yes
CPU and Memory Efficiency	Good	Good	Varies	Varies
Forward Only	Yes	Yes	No	No
Read XML	Yes	Yes	Yes	Yes
Write XML	Yes	No	Yes	Yes
Create, Read, Update, Delete	No	No	Yes	No

Another useful link:
Does StAX Belong in Your XML Toolbox? By Jeff Ryan , to understand pros, cons and uses of different xml parsers. The above table can be find in this article.

Links for new features of JDK 5

2006-04-11T13:37:00.000-05:00

The Server Side featured entry
JDK 5 in Practice by Cedric Beust has list of JDK 5 features,
JDK 1.5 from Joshua and Neal has list of JDK 5 features and when to use it.

Understanding Service Oriented Architecture

2006-04-07T17:06:00.001-05:00

Understanding Service Oriented Architecture: An article on familiar SOA at java.net . I liked the wrapping up sentence - "Service oriented architecture is a collection of ideas and patterns from the 1980s that survived the 1990s." Author David Walend has put together nice points about SOA.

As SOA is fast maturing, I see new definitions, challenges and ideas in the field. One of the major breakthrough will be giving systems choice to select most suitable service from a group of suitable services.

Till now Services have contracts with regards to messages. They specifies what kind of messages to they expect and what kind of messages they respond. These contracts still lack currencies with respect to time, cpu cycles and network bandwidth. Services are encapsulated and loosely coupled which makes SOA robust. Serives have independent life cycles and can be easily managed without breaking or stopping whole system. Orchestrator services are useful in workflow application. Assumption is orchestrator service already know most suitable service.

Performance tricks for data-intensive applications

2006-04-06T18:06:00.000-05:00

Performance tricks for data-intensive applications: "Performance tricks for data-intensive applications"

A quick preview of few points for large-scale data flow intensive applications.

Design enterprise applications with the EJB 3.0 Java Persistence API

2006-03-30T17:14:00.000-06:00

IBM Developerworks article by Borys Burnayev - Design enterprise applications with the EJB 3.0 Java Persistence API

Introductroy article, giving glimps of EJB3.0 and Java Persistence API (JPA) in Java EE 5.
Author's note - "You have two ways to define the mapping: metadata (annotations) and a mapping file. Although the metadata approach is heavily promoted, you should be mindful of the baggage it carries. The approach essentially entangles two logical layers of an application: the domain model and the mapping information. Being separate, these logical layers require separate testing using different techniques. The metadata approach doesn't hamper the testability of the layers per se. Rather, it causes two layers to appear to be one, which might or might not be a problem depending on a range of factors."

Point to be noted, just because annotations are promoted heavily, they do not fit everywhere.

Building an Really Simple Syndication (RSS) Java App

2006-03-29T09:50:00.000-06:00

Informit.com article - Java Reference Guide > Building an Really Simple Syndication (RSS) Java App: By Steven Haines.

Article explains about RSS and use open source project Informa to explain how to read rss feeds in a java application.

Crossing borders: Exploring Active Record

2006-03-09T18:07:00.000-06:00

Crossing borders: Exploring Active Record by Bruce Tate, an article at IBM developer works.

Since long I want to explore ROR. Bruce showed a area where ROR is different from Java. Active Records in ROR is simpler than what most of the Java Frameworks offers today. It also pointed to another framework RIFE. Which seems interesting, will read about it.

Notes on annotations vs xml

2006-03-06T13:23:00.000-06:00

"Hacking Log 4.0: Notes on annotations vs xml" from Andrew C. Oliver.

Andrew's point - "Prior to JDK 5.0, we had only XML as an option with various forms of preprocessing to simulate annotations. Now that we have the choice, what should we choose."

Enterprise Java Community: Struts action mappings: Divide Et Impera

2006-03-01T10:31:00.000-06:00

Enterprise Java Community: Struts action mappings: Divide Et Impera at TheServerSide.COM

One of the very nice article explaining the different combinations of a Struts action class and a form bean and how these combinations can be used. To the point article.

Best practices for Struts development - old

2006-02-22T18:06:00.000-06:00

A old article on IBM developerworks, Best practices for Struts development, but these points are good to remember. Good OOP practices too.

Summary:
1. Instead of putting all the attributes in one single ActionForm, split it across multiple ActionForms.
2. Instead of directly extending org.apache.struts.action.Action, create an Action class (IntermediateAction) by extending org.apache.struts.action.Action to handle common things in your application.
3. If session data is maintained as a single object and/or every page manipulates or uses session data. Use an abstract class by extending ActionForm and declare abstract methods (e.g. toSession(SessionData sessionData) and void fromSession SessionData sessionData)) for getting and setting SessionData. Make your ActionForm classes extend this class and implement abstract methods.
4. Handle common tasks related to exceptions in a abstract Action class. Let all Action class extend this class, and use the common exception handling class of the abstract base class.

Service Oriented Architecture (SOA) – Connecting the DOTS

2006-02-10T17:27:00.001-06:00

(Written by Sudhi, http://sudhilogs.blogspot.com/)

A Majority of enterprises have made expensive investments in enterprise information systems (EIS) over the years. A cost- effective solution is to enhance and evolve the existing EIS. Recent developments in Internet standards now make it easier for software applications to talk to each other, even if they're written in different languages or for different types of hardware. The advent of web services and Service Oriented Architecture (SOA) offers potential for lower integration costs and greater flexibility. Leading Fortune 1000 enterprises are aggressively and strategically deploying SOA across their enterprises. The Gartner Group published a survey, which indicated that more than 60% of companies in the Fortune 1000 will adopt SOA by 2006. SOA is built around the basic principle of breaking a business processes into reusable components and designing new business processes by utilizing the old and the new components. This approach had made many companies more service-oriented and, ultimately, more agile and responsive. Within SOA applications, information and other IT assets are viewed as services or “building blocks.” Each of these services can be mixed and matched to create new, flexible business processes. SOA treats elements of business processes and the underlying IT infrastructure as components that can be reused and combined to address changing business priorities and facilitate mergers and acquisitions. SOA has tremendous potential to shift revenue from packaged software to subscription services and from monolithic suites to composite applications. SOA is predicted to bring an evolutionary change in IT Systems management. Implementing extensive analysis and finding “hot spots” for integration is the key to success in implementing SOA. In addition, SOA has liberated the IT organization to more efficiently understand the business requirement as well as the tools and technology to deliver those integration services in a very rapid and cost-effective time frame. A perfect win-win!

SOA: Paradigm Shift
Recently, SOA development paradigm has emerged to focus on radically improving the efficiency of creating, modifying, extending, and repurposing solutions for enterprise application integration, process automation, and trading partner interchanges. The paradigm shift from traditional monolithic applications, followed by client server and distributed architecture has been a gradual one. With Monolithic applications being very tightly coupled and integrated, The idea behind SOA, which is more recent trend in application development being loosely coupled, seamless and less complex.

Figure 1: Application Development Trends

SOA redefines the concept of an application from being an opaque procedural implementation mechanism to that of an orchestrated sequence of messaging, transformation, routing, and processing events. With SOA, XML technologies allow applications to declare and expose both the message contents and the functional components that operate on the messages. XML-based development and deployment platforms that facilitate the SOA paradigm are highly compelling because they simultaneously reduce development and life cycle overhead substantially and enable an unprecedented extensibility and reusability of components and entire applications.

Business process management platforms based on the SOA paradigm facilitate the creation and execution of highly transparent and modular process-oriented applications and workflows that also conform to the typical IT departments' rigorous operational performance standards. The following attributes characterize process-oriented applications developed and executed within such an environment:

· End-to-end visibility of process activities, components, and functions
· Exposed and self-describing process components and functionality
· Process components that can be loosely coupled with any other component.
· The ability to integrate any information source and application functionality, no matter where they reside, into a process
· Process activities or components that can be added, removed or reconfigured without disrupting the process
· Processes that can be replicated, extended, and scaled easily.

SOA allows for the reuse of existing assets where new services can be created from an existing IT infrastructure of systems. In other words, it enables businesses to leverage existing investments by allowing them to reuse existing applications, and promises interoperability between heterogeneous applications and technologies. SOA provides a level of flexibility that wasn't possible before in the sense that:

Services are software components with well-defined interfaces that are implementation-independent. An important aspect of SOA is the separation of the service interface (the what) from its implementation (the how). Such services are consumed by clients that are not concerned with how these services will execute their requests.
· Services are self-contained (perform predetermined tasks) and loosely coupled (for independence)
· Services can be dynamically discovered
· Composite services can be built from aggregates of other services

Figure 2: SOA’s Find-Bind-Execute Paradigm

SOA uses the find-bind-execute paradigm as shown in Figure 1. In this paradigm, service providers register their service in a public registry. This registry is used by consumers to find services that match certain criteria. If the registry has such a service, it provides the consumer with a contract and an endpoint address for that service.

SOA-based applications are distributed multi-tier applications that have presentation, business logic, and persistence layers. Services are the building blocks of SOA applications. While any functionality can be made into a service, the challenge is to define a service interface that is at the right level of abstraction. Services should provide coarse-grained functionality.

Realizing SOA with Web Services
Web services are software systems designed to support interoperable machine-to-machine interaction over a network. This interoperability is gained through a set of XML-based open standards, such as WSDL, SOAP, and UDDI. These standards provide a common approach for defining, publishing, and using web services.

The greatest benefit of Web Services is it is very easy to build Integration Services. Integration Services are business-class Web Services that provide a high-level, business oriented interface to company’s internal business processes and systems. The interface provides a mechanism for disparate, heterogeneous distributed applications to talk to each other. There are two approaches to solve integration problems.

1. Study the existing business process and use integration technology to automate the process. This ends up pouring more concrete on those business processes rather than solving the actual business problem. In addition, these types of integration can be very IT-centric: we integrate the technologies we have, whether that meets the business requirements or not.

2. An Integration Service approach thinks first about the outcome and results we would like to deliver to the business. For instance, in the retail industry, having an Integration Service that reduces the time it takes to submit an order from web front end to main frame application has a measurable impact on the business. By taking that as a starting point, it becomes a lot easier to figure out what systems need to be tied together to deliver that service.

Most companies provide services to customers, clients, citizens, employees, or partners. Consider an illustration of service adoption in a business practice.

Use Case Scenario:
Consider the high-level architecture of an Order Management system (OMS). As is the case with any scalable, connected, and secure information system, an OMS consists of bringing information and functionality from distributed systems to diverse users in real time. Typically, the actors in this use case are Sales Rep., Partners, Order Approval Associates, IT resources, third-party vendors and suppliers, Channel partners, Credit Verification Authority and probably direct customers.

Web services: Problems it can solve:
If the OMS IT department leverages Web services, many traditional problems can be addressed:
· Connecting traditionally disconnected and autonomous software systems
· Enabling the construction of distributed infrastructures
· Creating dynamic, collaborative and adaptive applications
· Allowing diverse and redundant systems to be addressed through a common, coherent set of APIs
· Protecting and realizing existing IT investments without inhibiting the deployment of new capabilities
· Bringing information technology investments more in line with business strategies and business demand

Web services need persistence and query capabilities:
As discussed earlier, web services create huge amounts of new data, particularly the exchange of data-rich XML messages. These messages contain important information that many organizations will want and need to store, access, query, audit, analyze, and reformat.

It is impossible to persist all of these messages in a relational database because of the inflexible data model they impose. We must know what type of data the message will contain and configure relational tables to store it. Additionally, we will have to write code that knows, for every message type, how to handle the incoming message, interpret it, understand the header part, message part etc., and populate the tables.

Figure 3 The distinction between typical N- Tier implementation and SOA.

In case of a SOA implementation, the business logic encapsulated in business objects and hosted as Web Service. Using the SOA paradigm, the business service is executed by the user.

The complexity of the data and a typical WSDL describing each business service contains numerous specific methods, each returning a part of the overall content. To make all of the content available in a single view, the client application must make multiple Web service calls to each data source. Returned data must then be aggregated in such a way that it can be properly interpreted and used by the client.

Scenario details in case of typical Order Management System (OMS)
Sales Rep using the OMS
In this scenario, an in-house Sales Rep (typically a Tele Sales Rep) uses OMS to generate a quote for a real customer. Sales Rep will be saving the quotes in various document formats such as MS Word, Excel etc. The quote will be converted to an order, when the Customer sends a PO for the requested quote, after a series of price and product negotiations as required. The Order Details and Order tracking details will be sent to the Sales Rep, Sales Manager, customer etc.

A Field Sales Rep. may be using a PDA or some other wireless device in the field during sales visits to obtain similar information. In this case, the system must be able to detect the device type and provide a response with content appropriate for that device. This would require content transformation, such as: XML to HTML, SVG (scalable vector graphics), and CSV (comma-separated values), or other data formats.

Sales Manager and VP Sales
A Sales Manager would need sales reports pertaining to week, month, quarter etc.
The Sales Manager might also wish to get a high level picture as to how each business sector was performing in a quarter, what kind of products were selling well with customers, etc. Typically in such scenarios, a data warehouse is built by aggregating data from all sources and bringing the data into a Star or Snow-flake schema. This view will give the Sales Manager and VP Sales the overall performance of the sales team.

Warehouse Manager
when an order is placed by a Sales Rep, the OMS’s Warehouse component receives a PO and then sends a notification to the Warehouse Manager (WM). WM and the staff will have to make sure about the availability of the products. For products that are available, they will be made ready to ship to customers. For those that are not readily available in stock, the Warehouse manager will dispatch requests to manufacture/order it from partners as necessary.

Struts Tutorials - Jakarta Strut Tutorials

2006-02-09T14:22:00.000-06:00

Struts Tutorials - Jakarta Strut Tutorials"

The webpage suggests, "This complete reference of Jakarta Struts shows you how to develop Struts applications using ant and deploy on the JBoss Application Server. Ant script is provided with the example code. Many advance topics like Tiles, Struts Validation Framework, Java Script validations are covered in this tutorial."

It is a good effort and deserve a look.

Free XMLSpy Home Edition

2006-01-31T13:18:00.000-06:00

Get free XMLSpy Home Edition, it can also be integrated with Eclipse.

Its a nice tool to have. Makes lot of work easier when you are dealing with XMLs. Enjoy.

IBM Developerworks Article: Generate PDF files from Java applications dynamically

2006-01-27T09:16:00.000-06:00

IBM Developer Works has a article on using iText APIs to Generate PDF files from Java applications dynamically

Opensource project iText is simple to use, yet powerful API. I have used it to generate pdf files from Webmethods environment. This article explains how to use iText in Eclipse environment and walk through a sample application.

QG (Quick Guide) for Java Messaging System (JMS)

2006-01-20T16:34:00.000-06:00

JMS is used for messaging, a method for asynchronous and reliable communication between distributed components or applications. If you think RMI (Remote Method Invocation) analogous to phone calls, you can think of messaging analogous to email system.

Component of JMS

1. JMS provider: A messaging system that implements the JMS interfaces and provides administrative and control features.
2. JMS clients: The programs or components, written in the Java programming language, that produce and consume messages.
3. Messages: Objects that communicate information between JMS clients.
4. Administered objects: Preconfigured JMS objects created by an administrator for the use of clients. The two kinds of JMS administered objects are destinations and connection factories.

Messaging Domains:

1. Point to Point: Based on queues, intended for sending messages from a sender to a receiver. Sender pushes the message on queue; receiver pulls the message from queue.
2. Publish/Subscribe: Based on topic, intended for sending messages from a sender to multiple receivers. Sender addresses the message to topic, JMS system takes care of distributing it to subscribed receivers.

Message Consumption:

1. Synchronous: Call to the receive method, it blocks until a message arrives or can time out if a message does not arrive within a specified time limit.
2. Asynchronous: Register a message listener with a consumer. Whenever a message arrives at the destination, the JMS provider delivers the message by calling the listener's onMessage method.

Working of JMS system:

At JMS Provider side:

1. Create topic/queue at JMS Provider. Configure them in JNDI lookup space.

At Message Producer side:

1. Create connection to provider. Mostly using JNDI lookup of ConnectionFactory. e.g.

Context ctx = new InitialContext();
ConnectionFactory connectionFactory = (ConnectionFactory)
ctx.lookup("jms/ConnectionFactory");
Connection connection = connectionFactory.createConnection();

2. JNDI lookup for destination, which could be topic or queue. e.g.

Queue messageQueue = (Queue) ctx.lookup("jms/MessageQueue");

3. Create session and connection

Connection connection = connectionFactory.createConnection();
Session session = connection.createSession(true, 0);

4. Create message producer, messages and send them.
5. Close Connection. e.g. call to connection.close()

At Message Consumption side:

1. Create connection to provider. Mostly using JNDI lookup of ConnectionFactory.
2. JNDI lookup for destination, which could be topic or queue.
3. Create session and connection
4. Create message consumers, call receive() or use message listener to get the message
5. Close Connection. e.g. call to connection.close()

References:

[1] The J2EE 1.4 Tutorial, Chapter 33: The Java Message Service API

Naming on JBoss

2005-12-22T10:42:00.000-06:00

Naming on JBoss, this article from informit explains JNDI and JBossNS Architecture nicely. It is a sample chapter from book JBoss 4.0- The Official Guide by Marc Fleury, Scott Stark.

It goes through the fundamentals of JNDI and uses JBossNS as an example to explain how to use it in the real world.

Coupling and cohesion

2005-12-14T15:11:00.000-06:00

Well a lot is a talk about loose coupling and high cohesion in Java world and OO Programming in general. So just for reference here is excerpts from tutorial "Coupling and Cohesion: The Two Cornerstones of OO Programming" (Link: http://javaboutique.internet.com/tutorials/coupcoh/). Tutorial discusses the matrices for measuring coupling and cohesion in OO Programs.

"Object-oriented programming has two main objectives: to build highly cohesive classes and to maintain loose coupling between those classes. High-cohesion means well-structured classes and loose coupling means more flexible, extensible software."

"Cohesive means that a certain class performs a set of closely related actions. A lack of cohesion, on the other hand, means that a class is performing several unrelated tasks. Though lack of cohesion may never have an impact on the overall functionality of a particular class or of the application itself the application software will eventually become unmanageable as more and more behaviours become scattered and end up in wrong places."

"Whenever one object interacts with another object, that is a coupling. In reality, what you need to try to minimise is coupling factors. Strong coupling means that one object is strongly coupled with the implementation details of another object. Strong coupling is discouraged because it results in less flexible, less scalable application software. However, coupling can be used so that it enables objects to talk to each other while also preserving the scalability and flexibility."

"In OO programming, coupling is unavoidable. Therefore, the goal is to reduce unnecessary dependencies and make necessary dependencies coherent."

Book: JBoss at work

2005-12-02T11:29:00.000-06:00

JBoss at work is fast and easy way to stat with JBoss and J2EE. I will highly recommend it for the beginners.

Reference:
1. http://www.xpressionsz.com/?p=717
2. http://www.jbossatwork.com/

Java runtime.exec and Windows dir command

2005-11-15T17:29:00.000-06:00

If you would try to run windows "dir" command, using 'Runtime.getRuntime().exec' you will get exception "java.io.IOException: CreateProcess: dir error=2"

Because, 'dir' is not an executable program. See for details "When Runtime.exec() won't" [web:http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html?].

Solution: run command.com (or cmd.exe) and specify dir as input parameter to it. e.g. cmd.exe \C dir *.java

Using Java 1.4 feature - 'assertion', in Eclipse

2005-11-11T14:26:00.000-06:00

To enable compilation of program using keyword 'assert', 'javac' is needed to invoke with flag -source 1.4.

In Eclipse, go to Project->Properties->Java Compiler->Compliance and Classfiles (Use Configure Workspace Settings, if using workspace setting)

1. Uncheck 'Use default compliance settings'
2. Select generated .class files compatibility: "1.4" and
Source Compatibility "1.4"

Click "Apply". It may re-build the application.

To run the program with assertion enabled, it is needed to specify '-ea' or '-enableassertion' jvm flag.

In Eclipse, go to Run->Run...
1. Select the application you want to run in the left pane.
2. Select argument tab in the main pane.
3. Specify '-ea' or '-enableassertion' as VM arguments. Click Run.

For more assertion details see:
1. "Programming With Assertions", web: http://java.sun.com/j2se/1.4.2/docs/guide/lang/assert.html#usage-conditions
2. "Using Assertions in Java Technology" web: http://java.sun.com/developer/technicalArticles/JavaLP/assertions

Event Driven Architecture (EDA)

2005-10-31T09:22:00.000-06:00

A quick introduction to EDA at WebMethods website.

Design a simple service-oriented J2EE application framework - JavaWorld Article

2005-10-21T13:00:00.000-05:00

Nice article for the beginners of SOA in JavaWorld.

Ambiguous overloading

2005-10-18T14:36:00.000-05:00

Following code will
----------------------------------------------------
public class TestClass {

public void foo(Object o)
{
System.out.println("foo(Object o)");
}

public void foo(String s)
{
System.out.println("foo (String s)");
}

public static void main(String args[])
{
TestClass question = new TestClass();
question.foo(null);
}

}
-------------------------------------------------------
print "foo (String s)",
but following is error

----------------------------------------------------
public class TestClass {

public void foo(Object o)
{
System.out.println("foo(Object o)");
}

public void foo(String s)
{
System.out.println("foo (String s)");
}

public void foo(Integer i)
{
System.out.println("foo(Integer i)");
}

public static void main(String args[])
{
TestClass question = new TestClass();
question.foo(null);
}

}
-------------------------------------------------------

Reference:
[1] http://www.angelfire.com/or/abhilash/Main.html

IBM donates Rational processes to Eclipse

2005-10-17T16:53:00.000-05:00

Java World reports that IBM is contributing a subset of the company's Rational Unified Process (RUP) product, helping to create new streamlined process, called the Eclipse Process Framework. Also, fifteen other companies have signed on to contribute code and processes to the proposed framework, including Cap Gemini Ernst & Young, Covansys, Number Six Software, Armstrong Process Group, Object Mentor, and Bedarra Research Labs.

Hope to meet you soon, Eclipse Process Framework.

QG (Quick Guide) for XML SAX-Parser Programming

2005-10-04T22:43:00.000-05:00

"The Simple API for XML (SAX) is the event-driven, serial-access mechanism that does element-by-element processing."[1]

Packages:
(1) javax.xml.parsers: APIs for a common interface for different vendor's SAX and DOM parsers
(2) org.xml.sax: basic SAX APIs
(3) org.xml.sax.helpers : contains "helper" classes

To have a SAX Parser
1. extend DefaultHandler, provide methods for events like
startDocument(),
startElement(String uri, String localName, String qName, Attributes atts),
endElement(String uri, String localName, String qName),
endDocument(),
characters(char[] ch, int start, int length) and others.
2. get SAXParserFactory object using static method SAXParserFactory.newInstance();
3. get parser, call newSAXParser() method of SAXParserFactory object
4. call parse method of the parser, pass the handler object you created.

Exception for Non-Validation Parsers - org.xml.sax.SAXParseException, more general is SAXException. SAXParserFactory class can throw an exception exception if it cannot create a parser - ParserConfigurationException, such an error might occur if the factory cannot find the class needed to create the parser.

ignorableWhitespace() event can be used for validating parser. Use factory.setValidating(true) for same.

For schema support use factory.setNamespaceAware(true); too. Also, handle appropriate exceptions, eg SAXNotRecognizedException

REFERENCE:
[1] "Chapter 5:Simple API for XML, The J2EE 1.4 Tutorial" http://java.sun.com/j2ee/1.4/docs/tutorial/doc/

[2] "The SAX standard page" http://www.saxproject.org/

ONJava.com: What Is a Portlet

2005-10-04T20:36:00.000-05:00

ONJava.com: What Is a Portlet

Nice explanation about Portlets.

java.util.prefs.Preferences Class

2005-10-01T12:02:00.000-05:00

Anthony suggested use of "Preferences" class to store user preferences. Included from Java1.4 "Preferences" is a better way to store key/value pairs than using ".REG" file (see last post). Here are few notes and references on using "Preferences" --

"A node in a hierarchical collection of preference data. This class allows applications to store and retrieve user and system preference and configuration data. This data is stored persistently in an implementation-dependent backing store. Typical implementations include flat files, OS-specific registries, directory servers and SQL databases. The user of this class needn't be concerned with details of the backing store." [1]

"The java.util.pref.Preferences class, which was added in Java 1.4 to provide improved functionality over the java.util.Properties class, is used to store and get persistent (remains on disk between program executions) hierarchical name/values pairs. These preferences are stored in an operating system dependent manner, eg in the Windows registry, a Mac preferences file, or in a Unix do file. Both system and user preferences can be obtained." [2]

"By convention, a preference node is associated with a Java package. For example, if a class called com.mycompany.Foo needs to save some preferences, it would save them in the preference node associated with the package com.mycompany.

There are two types of preference nodes: a system type and a user type. A system node is shared by all users of a system. Any changes made to a system node are immediately visible to all users of the system. A user node is a node whose values are accessible only by the user using the application." [3]

"Every Preferences implementation must have an associated PreferencesFactory implementation. Every J2SE implementation must provide some means of specifying which PreferencesFactory implementation is used to generate the root preferences nodes. This allows the administrator to replace the default preferences implementation with an alternative implementation.

Implementation note: In Sun's JRE, the PreferencesFactory implementation is located as follows:

1. If the system property java.util.prefs.PreferencesFactory is defined, then it is taken to be the fully-qualified name of a class implementing the PreferencesFactory interface. The class is loaded and instantiated; if this process fails then an unspecified error is thrown.
2. If a PreferencesFactory implementation class file has been installed in a jar file that is visible to the system class loader, and that jar file contains a provider-configuration file named java.util.prefs.PreferencesFactory in the resource directory META-INF/services, then the first class name specified in that file is taken. If more than one such jar file is provided, the first one found will be used. The class is loaded and instantiated; if this process fails then an unspecified error is thrown.
3. Finally, if neither the above-mentioned system property nor an extension jar file is provided, then the system-wide default PreferencesFactory implementation for the underlying platform is loaded and instantiated." [1]

References:
[1] http://java.sun.com/j2se/1.5.0/docs/api/
[2] "Java: Preferences" http://leepoint.net/notes-java/41io/30properties_and_preferences/10preferences.html
[3] "The Java Developers Almanac 1.4", http://javaalmanac.com/egs/java.util.prefs/BasicGetSet.html?l=rel

Using windows registry to store values

2005-09-30T17:49:00.000-05:00

I came across an interesting approach to store attributes today. A Java program needed few attributes like username, mailserver host, mailbox and password. These values are specific to user running the program.

Developer used windows registry entry to store these values. She provide a ".REG" file where she had sample values. When user will run the .REG (simply by double clicking), these values will be loaded into the windows registry. The program then pulls out these values by calling windows utility "reg query".

This ofcourse will only work on windows platform. And is not the best approach, but yes, it solves the purpose.

Here is an example of a .REG file.

***** .REG file begin *****
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\MYSETTINGS]
"servertype" = "imap"
"host" = "ABCD"
"mailbox" = "INBOX/TEST"
"username" = "USER"
"password" = "QWERTY"
"maxcount" = "50"
***** .REG file end *****

JavaMail API

2005-09-30T17:21:00.000-05:00

JavaMail API:
Use it to get email related functionality in your java programs. As suggested on the webpage - "The JavaMail API provides a platform-independent and protocol-independent framework to build mail and messaging applications. The JavaMail API is implemented as a Java platform optional package and is also available as part of the Java platform, Enterprise Edition."

Apache Ant

2005-09-29T23:02:00.000-05:00

Apache Ant - A must know for all J2EE personals. Find its manual at http://ant.apache.org/manual/index.html

Getting Started with JBoss 4.0

2005-09-29T22:05:00.000-05:00

Getting Started with JBoss 4.0: "Getting Started with JBoss 4.0"
Good guide for beginers in J2EE/JBoss.

Meet Eclipse

2005-09-11T13:10:00.000-05:00

Know more about Eclipse in the article Meet Eclipse at developer.com . Call it IDE or RCP (rich client platform), it keeps on amazing me. This article touches basics of Eclipse, suggests resources to find more about it. Whether you have just started using eclipse or a expert, you would enjoy this article.

What amused me most was visual studio ad kept playing in sidebar. I wonder if there is C# plug-in for Eclipse! Well, even if there is one, I don't think I am going to use that in near future.

Few resources suggested in the article:

1. Eclipse Web site: http://www.eclipse.org
2. Planet Eclipse: http://www.planeteclipse.org
3. Eclipse Plugin Central: http://www.eclipseplugincentral.com
4. EclipsePlugins: http://eclipse-plugins.info
5. Eclipse Zone: http://www.eclipsezone.com
6. IBM developerWorks: http://www.ibm.com/developerWorks
7. Eclipse Projects: http://www.eclipse.org/projects/

JMeter - Java Performance Analysis Tool

2005-09-02T11:07:00.000-05:00

I found two JMeter's -
1. Apache JMeter(http://jakarta.apache.org/jmeter/) and
2. HP JMeter (http://www.hp.com/products1/unix/java/hpjmeter/)

JMeter helps profile java application, capture and view performace data etc. This tool is useful for load and stress performance validation, capacity planning, trend detection, finding out software failure rate and many more.

Java text search - Apache Lucene

2005-08-31T21:47:00.000-05:00

Lucene! Apache Lucene is a text search engine library written entirely in Java. This is a library which I would be working with in near future. I will post more it soon. At the same time I would be looking for more links and projects related to Lucene.

Getting Started with Eclipse and the SWT

2005-08-31T19:33:00.000-05:00

Web page with tutorials and useful links to programming with Eclipse and Standard Widget Toolkit (SWT).
Good resource.

JavaWorld Article: Become an Eclipse hotkey showoff

2005-08-29T14:01:00.000-05:00

Become an Eclipse hotkey showoff: "Javaworld article - Become an Eclipse hotkey showoff
Tips for using the Eclipse IDE, is a short one but has few important Eclipse hotkeys.

OpenWFE - open source work flow engine

2005-08-28T16:08:00.000-05:00

OpenWFE is open source work-flow engine written in java. It also provides business process management suite. It is made of four servers: an engine, a worklist, a reactor (host for automatic participants) and a webclient (a generic demo web application).
By defaults it stores data in XML files. It can be configured to use MySQL and PostgreSQL.

Manning Publications

2005-08-24T16:43:00.000-05:00

Manning Publications Co. has published great Java J2EE books. Visit their homepage at www.manning.com

Java Certification Guides

2005-08-21T01:28:00.000-05:00

:: Java Certification Guides ::
You get certification guides for SCJP, SCBCD, SCWCD, SCDJWS and also study guides for ICAD and quiz for SCDJWS.
This is a nice source to keep one refreshed about Java Programming.

Eclipse Shortcuts

2005-08-12T17:56:00.000-05:00

Eclipse Shortcuts There is a collection of eclipse shortcuts here.

Migrate apps from Internet Explorer to Mozilla

2005-07-29T13:00:00.000-05:00

Migrate apps from Internet Explorer to Mozilla: "Migrate apps from Internet Explorer to Mozilla" Article at IBM developerworks.

Though not exactly related to Java. In a interview, I was asked about cross-browser references, this article seems to address that.

Java Random Numbers

2005-07-21T11:09:00.000-05:00

Java Random Numbers: "Random Numbers in Java by Doug Baldwin"

Author suggests "Java has a rich toolkit for generating random numbers, in a class named "Random". This document is a quick guide to using Random."

Use of Sun java packages

2005-07-20T11:04:00.000-05:00

I used sun.misc.Base64Coder class, and looking for the documentation of the same. I found this little note

"The classes under sun.* are Sun proprietary and are intended
for use only by the Sun JDK implementation or related Sun-internal use.
They are not part of the standard core Java api and are subject to
removal or incompatible changes at any time and in any release.
Therefore, we do not document them in order to discourage their use."

@ http://archives.java.sun.com/cgi-bin/wa?A2=ind9910&L=java-security&F=&S=&P=191

Java Package Tutorial (English version)

2005-07-20T11:00:00.000-05:00

Java Package Tutorial (English version): "Java Package Tutorial" by Patrick Bouklee.
He truly suggests "Packages are nothing more than the way we organize files into different directories according to their functionality, usability as well as category they should belong to."

Java Reference Guide

2005-07-11T09:16:00.000-05:00

Java Reference Guide: "Java Reference Guide"
Steven Haines has a nice Java Guide at informit.com. The guide is quite latest, content is good from J2EE per se.

Java Collection Framework- HashSet & TreeSet Classes

2005-07-08T10:09:00.000-05:00

Java Collection Framework- HashSet & TreeSet Classes: "HashSet & TreeSet Classes"
Short note on what is the difference between them and how to use them.

Jazillian: How to Convert C to Java

2005-06-27T09:21:00.000-05:00

Jazillian: How to Convert C to Java: "How to Convert C to Java"
List of few notable differences between C and Java.

The Collections Framework

2005-06-23T13:01:00.000-05:00

The Collections Framework: "The Collections Framework"
Sun's reference on collection framework of java. It has API references, Tutorial, API Enhancements and FAQ

Reference Library

2005-06-17T11:58:00.000-05:00

Reference Library
Bunch of online books. Many on Java.

J2SE1.4 introduced New I/0

2005-06-15T09:18:00.000-05:00

I was working on the problem of copying one file from one location to other. Similar to the one described in a thread at JavaRanch. found couple of pointers on java nio.

1. J2SE: New I/0
2. Top Ten New Things you can with NIO

Schema for Object-Oriented XML

2005-06-13T10:56:00.000-05:00

Schema for Object-Oriented XML: "Schema for Object-Oriented XML 2.0"
In addition to XML schema and DTD, SOX(Schema for Object-Oriented XML) is also popular. xCBL is an example where SOX is used

Designing Web Services with the J2EE(TM) 1.4 Platform: JAX-RPC, SOAP, and XML Technologies

2005-06-02T01:00:00.000-05:00

Designing Web Services with the J2EE(TM) 1.4 Platform: JAX-RPC, SOAP, and XML Technologies

A Basic UNIX Tutorial

2005-06-02T00:45:00.000-05:00

A Basic UNIX Tutorial: "A Basic UNIX Tutorial"

Unix info Pages

2005-06-02T00:43:00.000-05:00

Unix info Pages: "Unix Docs"

FAQ for Various Internet Related Technologies

2005-06-01T20:18:00.000-05:00

irt.org Home Page: "irt.org Home Page"

XML.com: Describing your Data: DTDs and XML Schemas

2005-06-01T20:08:00.000-05:00

XML.com: Describing your Data: DTDs and XML Schemas: "DTDs and XML Schemas"

JavaRanch SCWCD Links

2005-05-31T10:03:00.000-05:00

JavaRanch SCWCD Links: "JavaRanch SCWCD Links"
Important links and mock exams, gives a good idea of questions on JSP, servlet and related.

Chapter 8 Continued: Connection Pooling

2005-05-29T15:49:00.000-05:00

Chapter 8 Continued: Connection Pooling: "Chapter 8 Continued: Connection Pooling"
Sun's Document on Connection Pooling

Autoboxing

2005-05-28T10:53:00.000-05:00

Autoboxing: "Autoboxing"
One of the many new features of Java 1.5.

Sun Microsystems

2005-05-26T10:54:00.000-05:00

Sun Microsystems: "Sun Forum FAQ Sets"
More Java FAQs

Object Serialization

2005-05-26T09:59:00.000-05:00

Object Serialization: "Object Serialization"
From Sun - documents, specifications, examples, FAQ on object serialization.

Designing Web Services with the J2EE(TM) 1.4 Platform: JAX-RPC, SOAP, and XML Technologies

2005-05-26T08:49:00.000-05:00

Designing Web Services with the J2EE(TM) 1.4 Platform: JAX-RPC, SOAP, and XML Technologies
Free online E-book on Web Services from Java BluePrints.

Java Frequently Asked Questions ( FAQ )

2005-05-25T22:52:00.000-05:00

Java Frequently Asked Questions ( FAQ )
Many java questions, answers and online resources.

WebSphere Knowledge Base

2005-05-25T19:58:00.000-05:00

WebSphere Knowledge Base: "WebSphere Application Server Knowledge Base"

Quick Hibernate - JAVA J2EE PORTAL

2005-05-25T19:45:00.000-05:00

Quick Hibernate - JAVA J2EE PORTAL: "Quick Hibernate"

Java Thread Primitive Deprecation

2005-05-24T10:22:00.000-05:00

Java Thread Primitive Deprecation: "Why Are Thread.stop, Thread.suspend,
Thread.resume and Runtime.runFinalizersOnExit Deprecated?"
See what Sun's document is saying on this widely asked question.

Welcome to Freewarejava.com, the place to find free Java applets, tutorials, references, Java books, and more!

2005-05-23T21:22:00.000-05:00

Welcome to Freewarejava.com, the place to find free Java applets, tutorials, references, Java books, and more!
Free Tutorials, Books, Scripts and others.

JavaScript and HTML Interview Questions

2005-05-22T19:47:00.000-05:00

JavaScript and HTML Interview Questions: "JavaScript and HTML Interview Questions "
Basic questions with answers on JavaScript and HtML

Design Patterns---JavaCamp.org

2005-05-20T20:09:00.000-05:00

Design Patterns---JavaCamp.org

ActiveWireless Interview Tips by JavaCamp

2005-05-20T09:41:00.000-05:00

ActiveWireless Interview Tips by JavaCamp: "Java Job Interview Questions & Answers"
I liked the tips they have written. Its short and exact to the point. Like if you don't know the answer what to do. This helped in my strategy.

PointBase JDBC Basic Tutorial

2005-05-20T02:47:00.000-05:00

PointBase JDBC Basic Tutorial: "PointBase JDBC Basic Tutorial"
This is webpage discussing using Pointbase and JDBC. Sun's appserver for J2EE-1.4 comes with pointbase database. So, its good to know how to use pointbase and JDBC.

IBM Informix Guide to SQL: Tutorial

2005-05-19T23:14:00.000-05:00

Help

Oracle and SQL information index.

2005-05-19T23:01:00.000-05:00

Oracle and SQL information index.: "Oracle / SQL Info"