Friday, 30 December 2011

FACEBOOK Link Integration to your Website. Share Data on FaceBook.

Copy the below given code inside your Html Page <Body> Tag and enjoy the facebook share plugin.

<a name="fb_share" type="button"  share_url="Your Website URL">Share</a>
<script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share"
        type="text/javascript">
</script>



This code will help you to share your data from your website to facebook .Any other issue related to Web Design,Application Design based Java you may ping me :- javadevelopersguide@blogspot.com,


www.facebook.com/SOJAVA



Follow on FACEBOOK

Friday, 16 December 2011

Finding Position of an HTML element in JavaScript.

<script language="JavaScript">
function find_pos(event){
    pos_x = event.offsetX?(event.offsetX):event.pageX-document.getElementById("pointer_div").offsetLeft;
    pos_y = event.offsetY?(event.offsetY):event.pageY-document.getElementById("pointer_div").offsetTop;
}

</script>


Use in HTML Page.

HTml:-

onclick="find_pos(event);"

Thursday, 15 December 2011

MYSQL User format ID Generation

Generate defined/User defined format Serial No from Database .There may be some condition where
I found this type of query which will help you to find the user format no from database.No. like
001 to 999 .


The Query for MySQL:

select case  when (intfield_id<=9 ) then concat('00',cast(intfield_id as CHAR))
when (intfield_id<=99 and intfield_id>9) then concat('0',cast(intfield_id as char)) when
(intfield_id<=999 and intfield_id>9 and intfield_id>99) then concat('0',cast(intfield_id as char))
end columnname from test




Friday, 9 September 2011

Manoj.Blog: Java Script : Drop Down values in JAVA SCRIPT

Manoj.Blog: Java Script : Drop Down values in JAVA SCRIPT: Hello , This function will help you to find the combo box / drop down box values in java script and again set these values to FORM. functio...

Java Script : Drop Down values in JAVA SCRIPT

Hello , This function will help you to find the combo box / drop down box values in java script and again set these values to FORM.

function setVal()
{
alert("sdf");
var innerData=document.getElementById('totData').innerHTML;
var hdtit=document.getElementById('hdsubtit').value;
var hdvalue=document.getElementById('hdsubval').value;
alert(hdtit);
//Getting Selected Index
var v=document.frmSubject.ddsub.selectedIndex;
//Getting Text & Value
var textdata=document.frmSubject.ddsub.options[v].text;
var val=document.frmSubject.ddsub.options[v].value;
//set the value to Form hidden Field
document.frmSubject.hdsubtit.value=hdtit+","+textdata;
document.frmSubject.hdsubval.value=hdvalue+","+val;
if(hdvalue==0){
document.getElementById('totData').innerHTML=innerData+" "+textdata;
}else{
document.getElementById('totData').innerHTML=innerData+" "+textdata;
}
}




Any Quries ....?

You may contact.

Wednesday, 24 August 2011

Java : Causes of An Out Of Memory Error (Server Si...

Manoj.Blog: Java : Causes of An Out Of Memory Error (Server Si...: Out Of Memory Error (OOME) can be solve. But what is actually it is !!!

The literal cause of an Out Of Memory Error is simple: a given To...

Java : Causes of An Out Of Memory Error (Server Side )

Out Of Memory Error (OOME) can be solve.But what is actually it is !!!



The literal cause of an Out Of Memory Error is simple: a given Tomcat instance uses up all of the heap memory allocated to it, causing an application or server crash.

Thus, the errors themselves are not particularly puzzling. The reason why OOMEs have become such a persistent topic of discussion in the Apache Tomcat community is that they are difficult to trace to their root cause.

A stack trace will not show the cause, as the problem usually lies not with Tomcat, but the web application.

Meanwhile, the 'incorrect' web app code causing Tomcat to run out of memory is usually technically correct. That is to say, in any context other than a container managed environment, the code would be considered standard. It is easy to see why a developer might have trouble determining which 'correct' section of their code was incorrect.

Here are some of the most common root causes of an OOME:

  • a simple case of the heap size being too small
  • running out of file descriptors
  • more open threads than the host OS allows
  • code with high amounts of recursion
  • code that loads a very large file into memory
  • code that retaining references to objects or classloaders
  • a large number of web apps and a small PermGen








Error: error java.lang.OutOfMemoryError: PermGen space..

Error: error java.lang.OutOfMemoryError: PermGen space..



In the area of J2EE development this error is one of the prominent & frequent which is not detected by any memory tool, so its interesting to avoid .PermGen space or heap size (outof memory) error can be avoided by following solutions.............

Solution-1
export CATALINA_OPTS=”-Xms512m -Xmx512m” (ksh/bash)
setenv CATALINA_OPTS “-Xms512m -Xmx512m” (tcsh/csh)

Stop Tomcat server, set environment variable CATALINA_OPTS, and then restart Tomcat. Look at the file tomcat-install/bin/catalina.sh or catalina.bat for how this variable is used. For example,
set CATALINA_OPTS=”-Xms512m -Xmx512m” (Windows)
In catalina.bat or catallina.sh, you may have noticed CATALINA_OPTS, JAVA_OPTS, or both can be used to specify Tomcat JVM options. What is the difference between CATALINA_OPTS and JAVA_OPTS? The name CATALINA_OPTS is specific for Tomcat servlet container, whereas JAVA_OPTS may be used by other java applications (e.g., JBoss). Since environment variables are shared by all applications, we don’t want Tomcat to inadvertently pick up the JVM options intended for other apps. I prefer to use CATALINA_OPTS.
Solution-2
Change the Catalina.bat file in Tomcat/bin with following code.
Edit catalina.bat.If you do not have catalina.bat , contact me.
If you have the .bat file, open and search for CATALINA_OPTS
If the parameter is set to no value, set it to -Xms256m -Xmx512m -XX:MaxPermSize=256m and move it to the top of the file.
If the above doesn’t work revoke the changes did in the previous step, go to the last lines of the catalina.bat. Look out for %_EXECJAVA% %JAVA_OPTS%. It will be in a few lines.
Insert the parameter in those lines. Like the one below.
%_EXECJAVA% %JAVA_OPTS% -Xms256m -Xmx512m -XX:MaxPermSize=256m %DEBUG_OPTS% -Djava.endorsed.dirs=”%JAVA_ENDORSED_DIRS%” -classpath “%CLASSPATH%” -Dcatalina.base=”%CATALINA_BASE%” -Dcatalina.home=”%CATALINA_HOME%” -Djava.io.tmpdir=”%CATALINA_TMPDIR%” %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
Here i have removed %CATALINA_OPTS% from them, to avoid setting parameters more than once.



It will really help you.I was in trouble with my team mates.
But now you can Enjoy...................





Friday, 19 August 2011

Java :- DispatchAction Example ( Struts )







Above index.jsp , actionservlet,struts-cofig and Formbean & 2 jsp file like display.jsp,view.jsp for output .



The DispatchAction class (org.apache.struts.actions.DispatchAction) provides a way to group all related functions into a single action class. It’s a useful mechanism to avoid create separate action classe for each function.







Struts: Important Questions with Answer

1. What design patterns are used in Struts?



Struts is based on model 2 MVC (Model-View-Controller) architecture. Struts controller uses the command design pattern and the action classes use the adapter design pattern. The process() method of the RequestProcessor uses the template method design pattern. Struts also implement the following J2EE design patterns.

· Service to Worker

· Dispatcher View

· Composite View (Struts Tiles)

· Front Controller

· View Helper

· Synchronizer Token

2. What are the different kinds of actions in Struts?

The different kinds of actions in Struts are:

  • ForwardAction
  • IncludeAction
  • DispatchAction
  • LookupDispatchAction
  • SwitchAction

3. Can we have more than one struts-config.xml file for a single Struts application?

Yes, we can have more than one struts-config.xml for a single Struts application. They can be configured as follows:



>actionservlet-name>



org.apache.struts.action.ActionServlet





config



/WEB-INF/struts-config.xml,

/WEB-INF/struts-admin.xml,

/WEB-INF/struts-config-forms.xml






.....

4. What is DispatchAction?

The DispatchAction class is used to group related actions into one class. Using this class, you can have a method for each logical action compared than a single execute method. The DispatchAction dispatches to one of the logical actions represented by the methods. It picks a method to invoke based on an incoming request parameter. The value of the incoming parameter is the name of the method that the DispatchAction will invoke.



22.How to use DispatchAction?

To use the DispatchAction, follow these steps :

  • Create a class that extends DispatchAction (instead of Action)
  • In a new class, add a method for every function you need to perform on the service – The method has the same signature as the execute() method of an Action class.
  • Do not override execute() method – Because DispatchAction class itself provides execute() method.
  • Add an entry to struts-config.xml



23.What is the use of ForwardAction?

The ForwardAction class is useful when you’re trying to integrate Struts into an existing application that uses Servlets to perform business logic functions. You can use this class to take advantage of the Struts controller and its functionality, without having to rewrite the existing Servlets. Use ForwardAction to forward a request to another resource in your application, such as a Servlet that already does business logic processing or even another JSP page. By using this predefined action, you don’t have to write your own Action class. You just have to set up the struts-config file properly to use ForwardAction.



24.What is IncludeAction?

The IncludeAction class is useful when you want to integrate Struts into an application that uses Servlets. Use the IncludeAction class to include another resource in the response to the request being processed.



25.What is the difference between ForwardAction and IncludeAction?

The difference is that you need to use the IncludeAction only if the action is going to be included by another action or jsp. Use ForwardAction to forward a request to another resource in your application, such as a Servlet that already does business logic processing or even another JSP page.



26.What is LookupDispatchAction?

The LookupDispatchAction is a subclass of DispatchAction. It does a reverse lookup on the resource bundle to get the key and then gets the method whose name is associated with the key into the Resource Bundle.



27.What is the use of LookupDispatchAction?

LookupDispatchAction is useful if the method name in the Action is not driven by its name in the front end, but by the Locale independent key into the resource bundle. Since the key is always the same, the LookupDispatchAction shields your application from the side effects of I18N.



28.What is difference between LookupDispatchAction and DispatchAction?

The difference between LookupDispatchAction and DispatchAction is that the actual method that gets called in LookupDispatchAction is based on a lookup of a key value instead of specifying the method name directly.



29.What is SwitchAction?

The SwitchAction class provides a means to switch from a resource in one module to another resource in a different module. SwitchAction is useful only if you have multiple modules in your Struts application. The SwitchAction class can be used as is, without extending.



30.What if element has declaration with same name as global forward?

In this case the global forward is not used. Instead the element’s takes precendence.

31. What is DynaActionForm?

A specialized subclass of ActionForm that allows the creation of form beans with dynamic sets of properties (configured in configuration file), without requiring the developer to create a Java class for each type of form bean.



32.What are the steps need to use DynaActionForm?

Using a DynaActionForm instead of a custom subclass of ActionForm is relatively straightforward. You need to make changes in two places:

  • In struts-config.xml: change your to be an org.apache.struts.action.DynaActionForm instead of some subclass of ActionForm

name="loginForm"type="org.apache.struts.action.DynaActionForm" >

name="userName" type="java.lang.String"/>

name="password" type="java.lang.String" />

import org.apache.struts.action.DynaActionForm;



public class DynaActionFormExample extends Action {

public ActionForward execute(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response)

throws Exception {

DynaActionForm loginForm = (DynaActionForm) form;

ActionMessages errors = new ActionMessages();

if (((String) loginForm.get("userName")).equals("")) {

errors.add("userName", new ActionMessage(

"error.userName.required"));

}

if (((String) loginForm.get("password")).equals("")) {

errors.add("password", new ActionMessage(

"error.password.required"));

}
 

33. What is the life cycle of ActionForm?

The lifecycle of ActionForm invoked by the RequestProcessor is as follows:

  • Retrieve or Create Form Bean associated with Action
  • "Store" FormBean in appropriate scope (request or session)
  • Reset the properties of the FormBean
  • Populate the properties of the FormBean
  • Validate the properties of the FormBean
  • Pass FormBean to Action

Tuesday, 16 August 2011

Java : Auto Refresh for JSP / Servlet Page


//Set Auto Refresh to a JSP /Servlet Page






//5 is the the time in second


response.setIntHeader("Refresh",5);


Or













Just Enjoy...........




Friday, 12 August 2011

HTML:- Get Browser Closed Event

Getting the browser closed event ,before close we can get the event and do something.I need this This is needed when needed to set the session null or the session should be destoryed after closed the browser.By this we can achive that...........







script type="text/javascript"

function closeEditorWarning()

{

return 'Hey, What r u Doing ? Are you sure?'

}

window.onbeforeunload = closeEditorWarning;







Thursday, 11 August 2011

Java :- How to Logout/Signout in Java

Logout In Java (JSP/SERVLET)



Many Questions..



how to disable back button of the browser after logout?



Many Problems & questions I found when related to logout/signout .After signout/logout the browser

Back button is working and a user can go inside or previous page without again login.Once you logout/signout ,i.e. you cannot go to your working page without once again new login.But , there was

a problem after Logout/Signout the Back button is working.To avoid this for implementing proper logout/signout I solve this....



Steps:-



1. set the Session to Null (Do not invalidate the session if the jsp use other session including Login)



session.setAttribute("facultyList",null);



2. Set the necessary Header to Every Jsp having Logout/Signout Link



//Forces caches to obtain a new copy of the page from the origin server

response.setHeader("Cache-Control", "no-cache");

//Directs caches not to store the page under any circumstance

response.setHeader("Cache-Control", "no-store");

//Causes the proxy cache to see the page as "state"

response.setDateHeader("Expires", 0);

//HTTP 1.0 backward compatibility

response.setHeader("Pragma", "no-cache");



3. Check the session (Username) in jsp ,if null the redirect to Login Page.



try{

mybean=(List)session.getAttribute("facultyList");

}catch(Exception ex){}

if(mybean==null){response.sendRedirect("index.jsp");}

else{

//Do normal }







Now it will work . Enjoy and Follow Me.







Wednesday, 10 August 2011

Manoj.Blog: Java :- Sending Data to Servlet From JSP

Manoj.Blog: Java :- Sending Data to Servlet From JSP

Java :- Sending Data to Servlet From JSP

Sending Data from Jsp to Servlet or Communication between Jsp & Servlet , we need certain things like ;-



1. A Jsp File

2. Deployment Descriptor (web.xml)

3. A Servlet File (Normal Java File)





Jsp File (index.jsp)



<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>















My JSP 'index.jsp' starting page



































Servlet File (test1.java)



Note : Here doGet/doPost/service method can be used.But I used here doGet(),becacuse the form action method is GET in index.jsp. So , I used doGet() in this example. But service method can use for both POST/GET method .But you can use any of these.



public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {



response.setContentType("text/html");

PrintWriter out = response.getWriter();

String name=request.getParameter("txtname");

out

.println("");

out.println("");

out.println(" A Servlet");

out.print("

Hi I am

");

out.print("

"+name+"

");

out.println(" ");

out.println("");

out.flush();

out.close();

}





Deployment Descriptor (Web.xml)









index.jsp





This is the description of my J2EE component

This is the display name of my J2EE component

test1

test1





test1

/test1











Note: In web.xml url-pattern is the path for browser ,so any name can be used (not /test1). we need & tag for run & map a servlet to the path. But, Url-pattern must match with the form action .







This is a simple Example for Communicate a servlet from jsp by passing a value Name or any Data.Enjoy..............the flavor of JAVA.



Posted By:- javadevelopersguide

Follow :- javadevelopersguide.blogspot.com















Java :- Setting Heap Size in Eclipse / My Eclipse


Error Jvm Heap Size (On Eclipse / My Eclipse)

I have set this feature in my IDE. I got this type of error when my team is on the project social network type project in struts framework.I was really in trouble , and seeking a solution finally I got the solution.It help U.


Heap memory related error java.lang.OutOfMemoryError.
What needs to be done here basically is to increase the jvm heap size. So for increasing the JVM Heap Size of Tomcat in Eclipse we have to set few VM arguments of the tomcat.
Follow the simple steps to change the Heap Size of Tomcat under Eclipse.
1. Open the Server tab in Eclipse and double click the Tomcat server to open Server Configuration.
2. In Server Configuration, click on the Launch Configuration link under General Information.
3. Under Arguments tab, add following values in VM arguments.
1
-Xms64m -Xmx256m