Java,Java,Java......

IndicThreads.com Conference On Java

2009-08-31T09:38:00.003+05:30

IndicThreads.com Conference On Java is going to held on 11th and 12th Dec '09 at Pune, India.

This is very intersting event especially for java passioniors and lovers. You can join the conference by visiting the website http://j09.indicthreads.com/ or clicking on the logo on the right side of this page displaying the event like this.

I hope you will enjoy the event and the future of java and many other intersting technologies. I love to be there.

Weblogic Portal Example

2009-08-10T12:49:00.000+05:30

Here I am going to make a simple example of Weblogic Portal.

Minimum requirements:

Weblogic Portals
Weblogic Workshop
Weblogic Server

Basically when you download weblogic portals then you will have all the necessary things already installed. It can be downloaded from http://www.oracle.com/technology/software/products/ias/bea_main.html

You have to download Oracle WebLogic Portal 10.3.

Step 1: Setting up the Weblogic Workshop

Open Weblogic Workshop from Programs -> Oracle Weblogic -> Workshop for Weblogic.
Change the perspective to Portal i.e. Window -> Open Perspective -> Others -> Portal.

Step 2: Create sample application

Create new Portal EAR project from File -> New -> Portal EAR Project.
Name it sampleEAR.
Click next and proceeds with default setting.
Create new PortalWEB project from File -> New -> Portal Web Project.
Name it sampleWEB.
Associate it with sampleEAR by clicking on checkbox if it is not selected and proceeds without any change.
Now select the WebContent, right click and select New -> Portal.
Name it myportal and proceeds.
You will see default portal in the workshop.
Create a jsp e.g. myjsp and then right click on it and click on Generate Portlet.
This will create a myjsp.portlet in application.
You can drag it from the Design Panel to the Portal.
Let’s create another portal which will access the url of the other website.
Right click on WebContent select New -> Portlet.
Name it myportlet and click next.
Select Browser (URL) Portlet.
On next screen in the Content URL input box type http://www.google.com.
Check the checkboxes :

Has TitleBar
Minimizable
Maximizable
Floatable
Deletable

Click next
Drag the portlet onto the portal.

Step 3: Deploy on server

Right click on the sampleWEB and select Run As -> Run on Server.
It will open the server window.
Select the Oracle Weblogic server from the dialog box and Click next.

These are the minimum steps to build a sample portal.

You can access the application by: http://localhost:7001/sampleWEB

Enjoy the sample..

Java + You

2009-07-15T14:53:00.001+05:30

"Java Is Dead, Long Live Java!" – The Future of Java

2008-08-04T09:10:00.000+05:30

"Java Is Dead, Long Live Java!" – The Future of Java
— 'Because of its prominence,' writes Bryan Taylor, 'Java gets a lot of attention and with it much criticism, some of it valid.' What many may not realize, Taylor notes, is that some big breakthroughs have arrived and that the Java development landscape is solving important problems. In this column he takes a view of where Java is going to go in the next year or two as these ideas gain traction.

Trackback URL : Click Here

Struts 2.1.2 Released

2008-07-09T11:26:00.001+05:30

Yesterday when I was on Google searching for something I found that Apache had released the latest Struts 2 version which is Struts 2.1.2, and promoted to "Beta" on 26 March 2008

You can download it from Struts Download Page

Struts 2 Hello World Example

2008-07-07T09:02:00.007+05:30

I had seen many new deveopers struggling against struts2 hello world example. So I decided to write a small example.
Below are the required libraries to run this example which are easily availabel

struts2-core-2.0.11
xwork-2.0.4
commons-logging-1.0.4
commons-logging-api-1.1
freemarker-2.3.8
ognl-2.6.11

The structure of the applictaion which I am following is (Eclipse IDE)
Struts2Demo
|---src
| |----org
| | |----vinod
| | | |----action
| | | | |----HelloWorld।java
|---struts.xml

|---WebContent
| |---jsp
| |---HelloWorld।jsp
|---index.jsp
|---WEB-INF
| |---lib
| |---web.xml

It is true that different IDE's use different structure, but at last when war is build they follow same structure.
Lets start...

HelloWorld.java

package org.vinod.action;

import com.opensymphony.xwork2.ActionSupport;

public class HelloWorld extends ActionSupport{

String greetings = null;

public String execute() throws Exception {
setGreetings("Hello World");
return SUCCESS;
}

/**
* @return the greetings
*/
public String getGreetings() {
return greetings;
}

/**
* @param greetings the greetings to set
*/
public void setGreetings(String greetings) {
this.greetings = greetings;
}

}

HelloWorld.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Struts 2 Example</title>
</head>
<body>
<s:property value="greetings"/>
</body>
</html>

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Struts 2 Example</title>
</head>
<body>
<s:action name="HelloWorldAction" executeResult="true"></s:action>
</body>
</html>

struts.xml

<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="hello" extends="struts-default">
<action name="HelloWorldAction"
class="org.vinod.action.HelloWorld">
<result>/jsp/HelloWorld.jsp</result>
</action>

</package>
</struts>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

Enjoy the struts2(most popular java framework today)

I had also written some more examples and some solutions of struts which can be easily found at
Struts 2 ajax drop down example
Struts 2 change <actionerror /> <actionmessage />
Struts 2 Session Check Interceptor
About Struts 2

Java Code Names

2008-07-04T10:11:00.008+05:30

Yesterday I was crawling web and found some intersting things about java. Firstly when java was release its name is Oak. After some time the creator of java found the name Java.

I found some of the intersting things like the code names of the reeases of the java which I am going to describe below.

VERSION CODE NAME RELEASE DATE

Version	Description of Code Name	Code Name	Date of Release
JDK 1.1.4		Sparkler	Sept 12, 1997
JDK 1.1.5		Pumpkin	Dec 3, 1997
JDK 1.1.6	A female character in Bible	Abigail	April 24, 1998
JDK 1.1.7	Roman cognomen used by several politicians	Brutus	Sept 28, 1998
JDK 1.1.8	Name of a person/Football club	Chelsea	April 8, 1999
J2SE 1.2	Playground	Playground	Dec 4, 1998
J2SE 1.2.1		(none)	March 30, 1999
J2SE 1.2.2		Cricket	July 8, 1999
J2SE 1.3		Kestrel	May 8, 2000
J2SE 1.3.1		Ladybird	May 17, 2001
J2SE 1.4.0		Merlin	Feb 13, 2002
J2SE 1.4.1		Hopper	Sept 16, 2002
J2SE 1.4.2		Mantis	June 26, 2003
J2SE 5.0 (1.5.0)		Tiger	Sept 29, 2004
Java SE 6		Mustang
Java SE 7		Dolphin

You can these names on the sun website.

Here is the brief history of java. Some of you wanted to know that how many packages are there in java when it is officially released well here are the some facts.

Java 1.0 - 212 classes in 8 packages

Java 1.1 - 503 classes in 23 packages

Java 1.2/2.0 - 1,520 classes in 59 packages

Java 1.3 - 1842 classes in 76 packages

Java1.4 - 2991 classes in 135 packages

Java 5.0 - 3562 classes in 166 packages

Deadly Combination

2008-06-13T09:23:00.002+05:30

Yes, Deadly combination!! It doesn't means that there would some super stars of the film who would go the devil place and finish him. No No !!

I am talking about the deadly combination used in the development of the web sites. I am talking about the tools used for the Java development. Any guesses so far....

Yes, they are Struts2, Spring, and Hibernate

I am currently working all these tools. I am amazed to see the power of all the three technologies and how they makes the life of a developer like me, so easy.
All of three would make your project a huge success.

Now talking about Struts2... It is great framework with the inbuilt Ajax tags that would help many developers. Many new features of the struts2 are marvelous.

Hibernate... I already told in my last post about this. Hibernate would provide you a greater facility for your data persistence. its in built architecture that is fully object oriented which makes it a powerful tool. And yes, not to forget about the HQL (Hibernate Query Language).

Spring... Again a master piece framework which lets you to do handle hibernate and specially the IOC (Inversion of Control) that lets programmers to walk to the higher level. Spring have many in built functionalities that help in various ways. One of them is scheduling of tasks. Before this you have to do manually write lots of code but now with a fewer code you can achieve greater flexibility.

So enjoy working with the deadly combination ......

Hibernate Rocks

2008-06-12T09:42:00.000+05:30

After few days working on hibernate I found it very interesting and useful tool for the developers. It allows to handle code more efficiently while working on the database part.
Since I am new to it I don't know all the features of the hibernate, but yes the features that I had used are tremendous and the code is more reliable and efficient.
All the connection management is handled by it. And specially the mapping files which allows us to connect to the database
i enjoyed working with it and hopes it will provide more features in the future.

Changing default style of / tag

2008-06-12T09:41:00.005+05:30

In struts 2 when you put <s:actionerror /> tag it displays the errors in the following way:

<ul>
<li>error 1</li>
<li>error 2</li>
</ul>

But sometimes it seems to be very ugly when displaying the dot (.) in the action errors or action messages

Below is a normal code that displays the tags in your customized way.
You can specify your own css for this

<s:if test="hasActionErrors()">
<s:iterator value="actionErrors">
<span class="errorMessage"><s:property escape="false" />
</span>
</s:iterator>
</s:if>

Alternatively you can change the file in the "/template/simple/actionerror.ftl” and put it in the /web-directory/struts/simple if using simple theme

Similar for <s:actionmessage /> tag.

Enjoy Struts

Session Check Interceptor

2008-06-12T09:38:00.003+05:30

There must be some way to check that the current session is valid or invalid. This can be done using interceptors in struts in a very easy way.
Here I am giving an example how to resolve this.

First of all we will make an interceptor named SessionCheck.java.

package com.demo.interceptors;

import java.util.Collections;
import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.config.entities.ResultConfig;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class SessionCheck implements Interceptor {

public void init() {
}

public void destroy() {
}

public String intercept(ActionInvocation invocation) throws Exception {
ActionProxy proxy;
proxy = invocation.getProxy();
Map session = ActionContext.getContext().getSession();
Map results = proxy.getConfig().getResults();
/*
* We are checking that the user
* that is set at login time is null or not
*/
if (session.get("user") != null) {

return invocation.invoke();
} else {
/* Here we are passing the result to an
* invalid page by specifying its location
*/
ResultConfig rc = new ResultConfig("invalid",
"org.apache.struts2.views.freemarker.FreemarkerResult",
Collections.singletonMap("location",
"/com/demo/interceptors/invalid.jsp"));
results.put("invalid", rc);

return "invalid";
}

}
}

Now in struts.xml put the following code

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
-----
---

<interceptors>

<interceptor name="SessionCheck"
class="com.demo.interceptors.SessionCheck" />
</interceptors>
<!—- We are using this because we want it to apply for each and every action -->
<default-interceptor-ref name="SessionCheck"/>

---
---
</struts>

Struts 2 Ajax drop down Example

2008-06-12T09:31:00.006+05:30

Struts 2 has emerged as boon for developers. But the documentation available is very small. So I had decided to give a brief demonstration of the ajax used in struts 2.

In this example when u select from one drop down the other will populate accordingly. You can use it as it is or play with it. Enjoy !!

Index.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>
<s:action name="ListingAction" executeResult="true"></s:action>

Listing.jsp

<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
<head>
<s:head theme="ajax" />
<title>Listing</title>
</head>
<script>
function show_details() {
dojo.event.topic.publish("show_detail");
}
</script>
<body>
<s:form id="frm_demo" name="frm_demo" theme="simple">
<table border="0">
<tr>
<td><s:select list="lstList1" name="lst"
onchange="javascript:show_details();return false;" ></s:select>
</td>
<td><s:url id="d_url" action="DetailAction" /> <s:div showLoadingText="false"
id="details" href="%{d_url}" theme="ajax"
listenTopics="show_detail" formId="frm_demo">
</s:div></td>
</tr>
</table>
</s:form>
</body>
</html>

Detail.jsp

<%@ taglib prefix="s" uri="/struts-tags"%>

<s:if test="lstList != null">
<s:select list="lstList"></s:select>
</s:if>

DetailAction.java

package ajaxdemo.action;

import java.util.ArrayList;
import java.util.List;

import com.opensymphony.xwork2.ActionSupport;

public class DetailAction extends ActionSupport {
private String lst;
private List lstList = null;
private List lstList2 = null;

public String execute() throws Exception {

if (getLst() != null && !getLst().equals("")) {
populateDetail(getLst());
return SUCCESS;
} else {
return SUCCESS;
}
}

private void populateDetail(String id) {
lstList = new ArrayList();
if (id.equalsIgnoreCase("Fruits")) {
lstList.add("Apple");
lstList.add("PineApple");
lstList.add("Mango");
lstList.add("Banana");
lstList.add("Grapes");
} else if (id.equalsIgnoreCase("Places")) {
lstList.add("New York");
lstList.add("Sydney");
lstList.add("California");
lstList.add("Switzerland");
lstList.add("Paris");
} else {
lstList.add("Other 1");
lstList.add("Other 2");
lstList.add("Other 3");
lstList.add("Other 4");
lstList.add("Other 5");
}
}

public List getLstList() {
return lstList;
}

public void setLstList(List lstList) {
this.lstList = lstList;
}

public String getLst() {
return lst;
}

public void setLst(String lst) {
this.lst= lst;
}
}

DetailListing.java

package ajaxdemo.action;

import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
import java.util.List;

public class ListingAction extends ActionSupport {
private List lstList1 = null;

public String execute() throws Exception {
populateDetail();
return SUCCESS;
}

private void populateDetail() {
lstList1 = new ArrayList();
lstList1.add("Fruits");
lstList1.add("Places");
lstList1.add("Others");

}

public List getLstList1() {
return lstList1;
}

public void setLstList1(List lstList1) {
this.lstList1 = lstList1;
}
}

Struts.xml

<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="demo" extends="struts-default">
<action name="ListingAction" class="ajaxdemo.action. ListingAction">
<result>/listing.jsp</result>
</action>
<action name="DetailAction" class="ajaxdemo.action. DetailAction">
<result>/detail.jsp</result>
</action>
</package>
</struts>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

Simple LDAP Authentication

2008-06-12T09:29:00.001+05:30

This is a simple example through which we will connect to the LDAP Server and authenticate user.
I have used ApacheDS Server as a LDAP Server.

Install ApacheDS server and run it.
Following is a servlet used. make login.html and use as it

Login.java

import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.naming.*;
import javax.naming.directory.*;
import java.util.Hashtable;

public class Login extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {

public Login() {
super();
}

protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

final String SUCCESS = "Success.html";
final String FAILURE = "Failure.html";
String strUrl = "login.html";
String username = request.getParameter("username");
String password = request.getParameter("password");

Hashtable env = new Hashtable(11);

boolean b = false;

env.put(Context.INITIAL_CONTEXT_FACTORY,
"com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldap://localhost:10389");
env.put(Context.SECURITY_AUTHENTICATION, "simple");
env.put(Context.SECURITY_PRINCIPAL, "uid="+ username +",ou=system");
env.put(Context.SECURITY_CREDENTIALS, password);

try {
// Create initial context
DirContext ctx = new InitialDirContext(env);

// Close the context when we're done
b = true;
ctx.close();

} catch (NamingException e) {
b = false;
}finally{
if(b){
System.out.print("Success");
strUrl = SUCCESS;
}else{
System.out.print("Failure");
strUrl = FAILURE;
}
}
RequestDispatcher rd = request.getRequestDispatcher(strUrl);
rd.forward(request, response);

}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
processRequest(request,response);
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
processRequest(request,response);
}
}

Enjoy LDAP!! :)

Performance Increase

2008-06-12T09:26:00.001+05:30

Many of us passes through the same situation of having a low performance of our application. But if you follow some of the tips and tricks below you will soon realize the increase in the performance.

Collections
Always assign size to ArrayLists and other collections. Ex:

Collection c = new ArrayList(10);

Strings
Always use

String abc = "I love Java";instead of
String abc = new String("I love Java");

JDBC
Always close these statements after use:

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn = DriverManager.getConnection("databaseUrl","username","password");
Statement stmt = conn.createStatement();
String strSql = "select * from abc";
ResultSet rs = stmt.executeQuery("strSql");// close these
stmt.close();
rs.close();
conn.close();
strSql=null;

Use only the required columns in select query:

Select FIRSTNAME,LASTNAME from PERSON;

instead of

Select * from Person;

JSP
Use session object as compared to hidden values, url rewriting and cookies

Use

System.out.print()

instead of

System.out.println();

wherever necessary

Everywhere Java

2008-06-12T09:25:00.000+05:30

Java is everywhere from your shoes to mars and from mobiles to big dream machines and from your favorite bike to space shuttles.

You can't even escape Java if you are a programmer or a developer.

Struts2

2008-06-12T09:23:00.002+05:30

Struts 2 is a new framework for the java developers. It is a combination of Struts 1 + Webworks formally known as Struts Ti. It is available with the enhanced quality of code and helps developers to work in a more organized way.

In built Ajax functionality is a boon for the developers. When I started working on the Struts 2. I felt that it may be very hard to learn but not actually. It is far easier then I thought. I haven’t work on other frameworks like Tapestry, Wicket, Spring etc. but I know what I am doing is good enough for me.

All frameworks provide there own way of style of coding which are good in there respect.

In built Interceptors provided a great functionality that helps in lots of situations. The one I like is a WaitAndExecute Interceptor. It is very helpful in situations when your action takes lots of time to execute. This interceptor displays a default page when your action is executing at background

Lots of more features are there for developers like Ajax functionality, themes to be used on pages, Inversion of Control.

I know that the documentation is little less but you know when a new technology grows it takes time. Struts 2 also one of them. The latest release of the Struts 2 is 2.0.11 which can be downloaded from Struts 2 home.

I had a Struts 2 forum on the nabble.com which can help you answer all your queries related to the Struts 2. You are welcome to post queries