The art of debugging

Software debugging is used to troubleshoot a problem in code.

So what is the best way of debugging?
1.  Run through the log statements
2.  Start  a debug session in your favourite IDE. The session can be remote(for a web app) or local.
3.  Narrow down to the problem by reducing the dependencies. Is it because of the framework or your own code, to know that  reduce the  code and test piece by piece.

Option 2, Debugger is the best arsenal for troubleshooting issues in code. Mixing 1,2 and 3 would be the ultimate way to fix the worst problem.
For details of remote debugging in eclipse please refer to my earlier posts.

In eclipse I find the below things very useful in debugging session:
  1. Breakpoints:
        1.Put a  breakpoint in eclipse. You can also edit the breakpoint properties by right clicking on the breakpoints           properties. Here you can put a condition and put S.o.p for quickly identifying the problem
       2. Exception breakpoint is a cool feature which will catch the exception which you specify. This will help you             find the control flow(especially with nasty Null pointer exceptions). You can specify this by clicking on the             "Add Java Exceptions" breakpoint of breakpoints view.

    2.If you're running in debug code, you can actually just edit
the method and re-invoke it. None of this resetting         variables on the
fly; just save the new method and do 'drop to stack' to get it to
re-run the code.
      You can't do this if you're not running your application in eclipse, but are rather joined to it as a remore                 debugger.

   3. Variables can be reset in debugging session through expressions or variables view.

   4. Short cuts:
              CTRL+SHIFT +I -- to check a variable after selection.
              F5, F6, F8

Useful links
Jacoozi - Remote Debugging with Eclipse

JNDI test JSP page

<%@ page language="java" pageEncoding="UTF-8" contentType="text/html;charset=utf-8" import="javax.naming.*" %>
<% InitialContext initialContext = new InitialContext();
   Object obj=initialContext.lookup("java:comp/env/jdbc/xmpPubPool");
   out.print(obj);
 %>

Useful Eclipse Plugins + shortcut keys

Here is a list of plugins and their usefulness:

• MyEclipse -- Is a heavy wieght champion among plugins.Has lot of good features that makes it good as well as bulky. It sucks lot of memory.

Swing Tools

• jigloo -- Very good, clean and free Swing code generator. Makes swing development like VB.

Code Analysis:

• pmd

Javascript:

• jsEclipse

• Teniga_Javascript_Editor

Miscellaneous

• Mylyn --- Connects to task repository and eases task managemnt.Also standalone support
• JadClipse --Uses Jad to decompile class
• jautodoc -- Very useful for quick API documentation.
• junitBuilder -- Generate Junit automatically for classes..Saves time
• moreunit - a must have for junit. http://moreunit.sourceforge.net/org.moreunit.updatesite/
• phpeclipse -- Good for PHP developers.
• VelocityWebEdit -- Cool velocity template validation and edit tool
• patternbox -- very useful for building regular expressions quickly.
• xmlbuddy -- neat small and simple xml editing tool.
• subclipse --SVN plugin
• NTail - tail for eclipse http://www.certiv.net/
• Eclipse HttpClient -- is a Rich HttpClient Plugin with stunning user interface and build on top of the famous Apache HttpClient
• Jar class finder - give a class , it will find the jar where it belongs to.

http://www.alphaworks.ibm.com/tech/jarclassfinder/download MDA tools/plugins ---These have the ability to generate j2ee code automatically based on model driven architecture

• andromda

AJAX Plugins

• aptana

DB Modelling

• Clay modelling tool DB_Modelling_jp.azzurri.clay

Short Cut keys : CTRL+E for switching editors.Ctrl + F6 to navigate between the open editors, CTRL+ F11 for executing last command. Refactoring ALT +SHIFT+R --rename variable ALT + SHIFT + M -- extract method Indentation CTRL + I -- correct indentation individually. CTRL + SHIFT + F -- whole page format. Creation: CTRL+ N. I found it much easier to press ALT + E (extend) to add extended class and ALT + A (add interface) to add interfaces in the new class wizard. My class will then come out with empty overridden methods and correct imports. Search CTRL+Shift+G, which searches the workspace for references to the selected method or variable. 5 stars. Agility F3 Go to a type declaration CTRL + SHIFT + UP(DOWN) -- move up or down to the next member CTRL+T on an interface name...This list the implementation of the interface. Very useful. 5 stars CTRL+. and CTRL+, Move to one problem (i.e.: error, warning) to the next (or previous). Ctrl-F6 is a great way to jump around between open editors. CTRL+F7 to switch views...Verrrry useful CTRL+F8 to switch perspectives. Ctrl-O in a class definition brings up Quick Outline. Start typing a member name and hit return once it’s unambiguous. Combined with Open Type this is a lightning fast way to go to any method in any class.ctrl-o ctrl-o to show inherited members too! Less typing

I think of Quick Fix as a tool for writing code, not something that just corrects accidental errors. Instead of trying to type perfect code and using Quick Fix only when you make a mistake, try intentionally leaving out code, then using Quick Fix to add it in. For example, call a function that isn’t defined, passing in all the arguments you want to to take. Use Ctrl-1, Enter to create an empty version of the function with all the right parameter types. I also like Quick Fix for creating casts. I assign an expression to a variable without a cast, then use Quick Fix to add it in.

Instead of declaring a variable and then assiging the value of an expression to it, try just writing the expression, then use Quick Assist – Assign to Field (Ctrl-2 L) to generate the declaration. The variable name will be highlighted and the drop down gives you several reasonable alternatives to use for the variable name. Tab again to get to the type to choose an alternative. For example if you had new ArrayList<String&gt;() and used Assign to Field you might choose List<String&gt; from the list of type alternatives.

More here : http://eclipse.dzone.com/news/effective-eclipse-shortcut-key

More here : http://rayfd.wordpress.com/2007/05/20/10-eclipse-navigation-shortcuts-every-java-programmer-should-know/

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linux tips

Tomcat Remote debugging in linux
Put the below in catalina.sh

JPDA_TRANSPORT=dt_socket
JPDA_ADDRESS=5005
$./catalina.sh jpda start

Startup script with logging: Create a file with the following and change the mode to executable under $catalina_home/bin ./startup.sh;tail -f ../logs/catalina.out For shutdown create as below: ./shutdown.sh;tail -f ../logs/catalina.out Restart script for linux: ./shutdown.sh echo "shutdown.sh executed" echo "Sleeping for 5 seconds after shutdown" sleep 5 ./startup.sh echo "starting up" echo "Sleeping for 1 second" tail -f ../logs/catalina.out Jar usage $cd portal-impl $jar xvf portal-impl.jar :extracts the jar file into portal-impl dir. $jar cvf portal-impl-patched.jar portal-impl/ :make jar file from portal-impl dir contents the jar will be having portal-impl as the root dir. To change ownership: $chown tomcat:tomcat FILE_NAME To change group: $chgrp tomcat FILE_NAME To Switch user: $su USER_NAME

Clear all unwanted .SVN files

find . -name ".svn"-exec rm -rf {} \;

JProfiler - A J2ee profiling tool

This is one of the best profiling tools i have seen.
They give a 10 day free evaluation with all feature's enabled.

Setting up the Jprofiler was a little tedious until I came to know how it works.
I was expecting that the Jprofiler would put some custom code in tomcat(like profiler4j) but actually it runs the tomcat in it's own session.

On windows, setup the application with downloaded exe.
Go to New -- Start center -- New Server integraion and you are done.
The app server gets started and log console is available through Jprofiler itself.

Another nice feature of jProfiler is remote connectivity. We can connect to server running in linux from windows.
To do that, install jProfiler on linux as below
 rpm -i http://download.ej-technologies.com/jprofiler/jprofiler_linux_5_0_1.rpm
Get the catalina.sh(for tomcat) and give to the start center wizard. Copy back this(jprofiler_startup.sh) to tomcat on linux. Now start the server using jprofiler_startup.sh.

Connect from windows GUI and you are ready for profiling..


The real thing :
Profiling can be done for memory or CPU load. The hot spots are the best ones to quickly find out the problem areas.
Also J2ee components can be easily profiled for JDBC calls, JMS calls,etc.





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Apache 2.x setup Quick guide for Linux

I am herewith trying to log all the issues faced during apache web server setup.
Download apache from http://httpd.apache.org/download.cgi

There you can find either a source or binary.

Normally it is good to compile the source to a OS platform. But it is little extra effort. Setting up using a apache binary is faster but may not be reliable.

Here are basic and advanced steps for apache setup:

To setup , follow these very basic steps to setup apache in it's default location
Extract the apache bundle

1. tar xvf apache.x.tar
2. cd apache.x
3. ./configure
4. make
5. make install
6. cd ./apache/bin
7. ./httpd -k start[stop] # run's on port 80 which is default

Open browser..Go to http://localhost/ #....This should open a page ...It Works!!

To make an advanced setup like configuring additional modules, setup destination,etc , do the following:

1. tar xvf apache.x.tar
2. cd apache.x
3. ./configure --prefix=/path/to/apache --enable-[auth]=shared
4. make
5. make install
6. cd ./apache/bin
7. ./httpd -k start[stop]


Go to ./apache/conf/httpd.conf to change the port or any other setting. Will blog later on httpd.conf .

To have apache use a custom httpd.conf on startup do this :
./httpd -k start -f /custom/conf/httpd-custom.conf

To chek if apache supports DSO, run
./httpd -l # this lists all the modules setup in apache

I have listed a set of modules which were enabled for apache 2.0.59 to run a website on production:

--enable-authn_file=shared --enable-authn_anon=shared --enable-authz_host=shared --enable-log_config=shared --enable-logio=shared --enable-expires=shared --enable-headers=shared --enable-setenvif=shared --enable-mime=shared --enable-status=shared --enable-vhost_alias=shared --enable-dir=shared --enable-alias=shared --enable-rewrite=shared --enable-access=shared --enable-auth=shared --enable-userdir=shared --enable-autoindex=shared --enable-negotiation=shared

There are thousands of directives to be configured in httpd.conf .Refer http://httpd.apache.org/docs/2.2/mod/directives.html for apache 2.2

To change the server port by changing in ./apache/conf/httpd.conf the Listen 80 directive

Virtual host directive : A single apache server can have multiple virtual hosts and can server different sites.

To set this, open ./apache/conf/httpd.conf and enter the directive as below:


<VirtualHost 172.20.41.39:80>
 ServerName xyz.com
 ServerAlias www.v2.xyz.com v2.xyz.com www.eetonline.com www.xyz.com eetonline.com

 DocumentRoot /web/docs/electronics/v3.xyz.com
 DirectoryIndex index.html index.htm
 ErrorDocument 403 /nopagefound.jhtml
 Redirect /uk/motorola http://www.xyznet.com/
 
 <Location "/globalSpec"> # to specifiy the mounted directory to be used
  ExpiresActive on
  ExpiresDefault "access"
  Header append Cache-Control "no-cache"
  Header append Expires "Thu, 4 Jan 1990 10:00:01 GMT"
  Header append Last-Modified "Tue, Jan 27 2099 23:59:59 GMT"
  Header append Pragma "no-cache"
  Options FollowSymLinks MultiViews
  satisfy any
  Order deny,allow
  Deny from all
  AuthType Basic
  AuthName "xyz login"
  AuthUserFile /web/admin/apache/etc/auth/xyz.com-globalSpec
  require valid-user
 </Location>
<VirtualHost>

Chess

Blind folded Chess I browsed a few sites for how to start off with blind folded chess. Infact the chess player need not be blind folded. He just needs not to see the board. The mind is the board, the scratch pad for tactics and thinking. Start with basic's ..Try moving pawns in your mind, then knights, then rook, bishop and then queen. Crafty is a nice little program to play blind folded chess. [www . craftychess . com] This follows algebraic notation and has only a command line interface. It clearly shows how the program is taking decisions. Really playing blind folded expands your mind tremendously. More to come as I explore this Blind folded!! Good chess links: http://susanpolgar.blogspot.com/ -- GM susan polgar's blog. http://www.rajaravisekhar.com/

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Spring portlet mvc and spring servlet mvc validation

Spring mvc is easy to get along with, unless we get the basic flow right. We end up wasting lot of time figuring out the flow of control/binding of errors for validation/etc. Spring portlet mvc validation

1. extend AbstractCommandController or SimpleFormController
2. In case of AbstractCommandController implement the method handleRenderView(req,res,command,errors)
3. Important thing to note is that you should return the ModelAndView as new ModelAndView(jspPage, errors..getModel());

• Note the method handleRenderView() is called even if validation fails. Hence we have to return back the command object having errors using errors.getModel().

Spring servlet mvc validation

• Implemented a simple form controller.

class ManageProfileController extend SimpleFormController { public ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception { Map modelMap = new HashMap(); return new ModelAndView(forwardJSP, modelMap); } }

• The configuration in *-servlet.xml is as below (assume dispatcher servlet is configured already)

<bean id="manageProfileController" class="com.TEST.web2.portlet.controller.common.ManageProfileController">        
        <property name="registrationService" ref="registrationService"/>
        <property name="formView"><value>common/manageprofile</value></property>
        <property name="commandClass"><value>com.TEST.web2.model.DpsUser</value></property>
<property name="validator" ><ref bean="userValidator"/></property>
      <property name="successView"><value>common/manageprofile</value></property>
    </bean>    

 On validation error, in servlet mvc, the onSubmit() is not called and the command object is available with errors.
To extract the errors in JSP use:


<spring:bind path="command.confirmPassword">
   <c:out value="${status.expression}"/>  <input name=confirmPassword type="password" style="width:200px; " onKeyUp="document.getElementById('cpw').value=this.value" value="<c:out value="${status.value}"/>">
    <font > <c:out value="${status.errorMessage}"/> </font>

</spring:bind>

Castor --The XML Marshaller

Forget writing XML parser...Castor will take care of parsing. It generates the java
classes to work with XML.

To use castor, -- put the below lib's in classpath -- ./lib/castor-0.9.9.jar ./lib/castor-0.9.9-srcgen-ant-task.jar ./lib/castor-0.9.9-xml.jar xercesImpl.jar; commons-logging.jar -- Run java org.exolab.castor.builder.SourceGenerator -i test.xsd -dest dtnFolder --optionally specify the package name if required. -- To convert from DTD to XSD use java org.exolab.castor.xml.dtd.Converter dtdFileName newXSDFileName To use the generated code:

• To run the unmarshal the castor lib should be in class path and follow the sample code herewith.

// Create a Reader to the file to unmarshal from
reader = new FileReader("test.xml");

// Marshal the person object
Person person = (Person)Unmarshaller.unmarshal(Person.class, reader);

• To marshal an instance of the person class you simply call the Marshaller as follows:

// Create a new Person
Person person = new Person("Ryan 'Mad Dog' Madden");
person.setDateOfBirth(new Date(1955, 8, 15));

// Create a File to marshal to
writer = new FileWriter("test.xml");

// Marshal the person object
Marshaller.marshal(person, writer);


Follow the document of castor for details.

LINUX usefuls

html'>linux basic commands:
ls
ls -a -- lists all files (hidden as well .)
ls -l -- list with permission and details

ln -s A B -- create soft link btw two file/folders

ps -- see current process
ps -e -- see background process as well
ps -H -- list process hierarchy
ps -f -- ?
pstree
top - see all proc's at one shot
pmap [PID] : list all the resource held by this proc.
cat /proc/[PID]/maps :

kill -3 [PID] -to get the status of threads
$ killall httpd -kill all the procs with name httpd

grep -- useful for search. Very powerful if we combine with other commands
eg: ps -ef | grep liferay == will return all the liferay process

fg -- bring the process to foreground
bg -- send the process to background
CTRL Z -- send the process to background..Can bring it to foreground using fg.
CTRL C -- close a program.

tail myfile.txt -n 100  -- list the last 100 lines in
            the file

mail -s "picture of me surfing" sylvia@home.com < surfing.jpeg  --- To mail a file
tail -f catalina.out --display the contents in real time
head -15 myfile.txt - Would display the first
            fifteen lines of myfile.txt.

diff -r -N folder1/ folder2/        ---find difference b/n folders.. -N do display diff content.


cat test.txt --display content of file test.txt

cat t.txt t2.txt > t3.txt -- merge t.txt+t2.txt= t3.txt

difference b/n folder
du -hs liferay1/webapps/* liferay2/webapps/*


touch file.txt -- quickly create a empty file

VI editor commands
i -- insert mode
r -- replace mode
/ -- search
:%s/fred/joe/igc : general substitute command(replace)
w -- write
wq --write and quit
q-- quit
:#20 - moving to a line 20
Ctrl u --page up
Ctrl d -- page down
:set number -- to set the number
~ Toggle case of the character under the cursor, or all visually-selected characters.
q: You can bring up the command line history while in Normal mode.
:42G -- ways to go to a particular line (line 42 for example)
Multiple Files Management

vim test xyz

:bn -- next file

:bp -- next file

:wn -- write file and move to next (SUPER)

Screen
Ref:  http://www.kuro5hin.org/story/2004/3/9/16838/14935

Screen is best described as a terminal multiplexer.
Using it, you can run any number of console-based
applications--interactive command shells,logging, curses-based
applications,
text editors, etc.--within a single terminal.Also can reattach again to
the screen even after logout.Excellent isn't it. Should have had a
separate blog :0). Any way the quick reference below:



$screen  --Start screen just by typing screen at your favorite command shell prompt

Ctrl a c --create another screen

ctrl a ctrl A --switch screen

ctrl a n -- switch next screen

ctrl a p -- switch prev screen

ctrl a A -- Give a name to the current screen.

ctrl a " -- to get a full-screen list of windows

ctrl a K --You can also kill misbehaving programs

$screen -r --will reattach the screen to the current session which.

Networking commands:

ping

netstat -- active connections
netstat -r --shows routing table


ifconfig (like ipconfig in windows)
ifconfig eht0 down -- shutdown lan card (to renew ip u can do this)
ifconfig eht0 up --startup lan card

iptraf
nmap -- port sniff
dig

NATing
/etc/hosts file
It is used to map simple human readable names with ip address.
Eg:
127.0.0.1 localhost.localdomain localhost
127.0.0.1 access.idp1.com

Installation
rpm -i foo-v123.rpm        ---install a package
rpm -i http://oss.oracle.com/kernel-2.4.20-18.10.1.i686.rpm
rpm -e foo
rpm -qi foo    -- To query a RPM package and display info
more details refer http://www.idevelopment.info/data/Unix/Linux/LINUX_RPMCommands.shtml

Autoexec.bat in linux
vi /root/.bashrc   # the user is root here.
---Do whatever needs to be done on login in the .bashrc
To load the properties without relogging in use : source /root/.bashrc

Secured remote copy:
scp <target1> <target2>
eg: scp test.zip sandeepm@xHost:/export/home/sandeep  -- copies the test.zip to the target2 from target 1.
scp sandeepm@xHost:/export/home/sandeep/test22.zip . -- copies the test22.zip from target2 to target1 .


Use grep recursively
You can  search recursively i.e. read all files under each directory for a string “192.168.1.5″

cd /etc

$ grep -R "192.168.1.5" *

Use grep to search words only
When you search for boo, grep will match fooboo, boo123, etc. You
can force grep to select only those lines containing matches that form
whole words i.e. match only boo word:

$ grep -w "boo" /path/to/file
Grep invert match
You can use -v option to print inverts the match; that is, it
matches only those lines that do not contain the given word. For
example print all line that do not contain the word bar:

$ grep -v bar /path/to/file
Count line when words has been matched
grep can report the number of times that the pattern has been matched for each file using -c (count) option:

$ grep -c 'word' /path/to/file

To get the DB conn list
$ netstat|grep -c app610

Shell script
The below will run a command for configurable no of times.
chmod +x test
usage : ./test [NO_TIMES] [COMMAND]

for ((  i = 0 ;  i < $1;  i++  ))
do
      echo "Executing $2";
       $2;
      sleep 1;
done

More scripts here http://www.usd.edu/~sweidner/lsst/
 


One of the best methods to capture a Unix terminal session is to use the `script` command.

In this example we start a script session, run a couple of commands,
and then use the `exit` command to stop capturing the terminal session:

$ script
Script started, output file is typescript
$ pwd
/home/will
$ ps
PID  TT  STAT      TIME COMMAND
11909  p0  Ss     0:00.05 -bash (bash)
25622  p0  S+     0:00.01 script
25623  p1  Ss     0:00.01 /usr/local/bin/bash -i
25624  p1  R+     0:00.00 ps
$ exit

Ref:
http://vim.wikia.com/wiki/Best_Vim_Tips

SVN/ Subversion Tips and traps

SVN could be tricky and waste a hell lot of time.

Case Issue :
Normally we run SVN server in linux. Our dev env will be in windows NT. Windows doest differentiate lower and upper case file names, while linux does. So when we try to do a SVN update, it gives wierd errors like Lock not released, while the problem is with Case.
This takes hours to sort out.


Merge branch to trunk
Often in a multi developer environment, it is required to maintain seperate branches so that the development is
not dependent on another developer. The developer takes a branch , works on his module and once done and tested,
merges it back to trunk.

Using tortoise svn, this can be achieved as follows:
1. right click on the root folder of your svn dump. Click merge .
2. Choose the revision from to for the branch (use show log to aid in choosing revision).
3. Make a diff. Do a dry run. Finally hit merge when satisfied.
4. Now the branch on ur local disk has the merged content. This can be commited to the trunk normally using commit.



More to come here.

apache commons configurator usage

commons configurator usage:
Download the below jars from apache site:
commons-collections-3.2.jar  application/octet-stream
commons-configuration-1.4.jar  application/octet-stream
commons-lang-2.3.jar  application/octet-stream

Usage of org.apache.commons.configuration class for dynamic property file reading is below:


 static PropertiesConfiguration config = null;
public void init(FilterConfig filterConfig) throws ServletException
{

try
{
 config = new PropertiesConfiguration(filterConfig.getInitParameter("ROBOT_FILE"));
 FileChangedReloadingStrategy reloadingStrategy = new FileChangedReloadingStrategy();
 reloadingStrategy.setRefreshDelay(1000 * 60 * 5);// 5 mins

 config.setReloadingStrategy(reloadingStrategy);
List patternsList = (List) config.getProperty("patterns");

} catch (ConfigurationException e)
{
 log.error(e);
}

}

By default the char seperator is "," and the list is automatically created.
Cool isnt it.


commons digester usage:

QuizResultsTO result = null; try { digester.addObjectCreate("quiz", "com.biomedcentral.business.imagelibrary.model.quiz.QuizResultsTO"); digester.addCallMethod("quiz/title", "setQuizTitle", 0); result = (QuizResultsTO) digester.parse(file); } catch (Exception e) { logger.error("Quiz configuration file not parseable", e); throw new TechnicalException(e); } return result.getQuizTitle();

setting datasource lookup from tomcat JNDI using spring

1.       -JNDI configuration is as below:

1.       Shutdown liferay/tomcat

2.       Modify applicationContext-hibernate.xml as below :

                       Replace
                       - <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">

         <property name="jndiName" value="jdbc/dmpPubPool" />  

         <property name="resourceRef" value="true" />

 </bean>

                       Instead of

-  <bean id="dataSource"

     class="org.springframework.jdbc.datasource.DriverManagerDataSource">

   <property name="url"><value>${hibernate.connection.url}</value></property>

   <property name="driverClassName"><value>${hibernate.connection.driver_class}</value></property>

   <property name="username"><value>${hibernate.connection.username}</value></property>

   <property name="password"><value>${hibernate.connection.password}</value></property>

 </bean>



Modify the JNDI path jdbc/dmpPubPool suitable for CMS.



3.    Add the context.xml(attached) into /META-INF/ folder of CMS webapp . Modify the JNDI path jdbc/dmpPubPool suitable for CMS.

This file has

<Context reloadable="true">

<ResourceLink name="jdbc/dmpPubPool" type="javax.sql.DataSource" global="jdbc/dmpPubPool"/>

<ResourceLink name="jdbc/adServerPool" type="javax.sql.DataSource" global="jdbc/adServerPool"/>

</Context>

4.       Update the server.xml of your liferay available under <liferay>/conf as below



<GlobalNamingResources>

           <Resource

               name="jdbc/dmpPubPool"

               auth="Container"

               type="javax.sql.DataSource"

               driverClassName="oracle.jdbc.driver.OracleDriver"

               url="jdbc:oracle:thin:@172.20.41.40:1521:xyz"

               removeAbandoned="true"

               maxActive="75"

               maxIdle="30"

               maxWait="-1"

               username="****"

               password="***"

               validationQuery="select 1 from dual"

       />

…..>



Copy ojdbc.jar available under cms/web-inf/lib into <LRay>\common\lib\ext

Modify the url and other settings as per your application.



5.       Remove all the org.springframework.jdbc.datasource.DriverManagerDataSource and use javax.sql.DataSource;

6.       Deploy CMS app and Startup liferay

7.       Test if the db connection is fine.



The ant script might not copy the META-INF/context.xml file. Modify the ant script for CMS with

                       <target name="build" depends="compile">

                                   <war>

…..

<!--Copy the META-inf library files -->

                       <zipfileset dir="${srcdir}/webapp/META-INF" prefix="META-INF/" />

                       ….

                 ……

External Javascript from Java Servlets

Copied from  http://myappsecurity.blogspot.com/2007/01 Like to thank anurag for the content.
/breaking-same-origin-barrier-of.html
External Javascript from Java Servlets

One of the lesser known sides of external JavaScript is the ability to reference a server side program(CGI, PHP or Servlets) instead of the familiar .js file. It is kinda interesting since a client side script interacting with a server side program is not considered safe and is usually not allowed from within the browser but apparently a script can be dynamically generated and loaded, if referenced in src attribute of the script tag, while the html page is being loaded. Using the src attribute of the script tag, we can call an external javascript, we can also call a server side program to dynamically generate a javascript. For example

script type="text/javascript" src="myservlet"

Where "myservlet" is the server side program and could be an absolute path like “http://www.myserver.com/myservlet” or a relative path like “myservlet” instead of the usual .js file. Interestingly you can even pass parameters to the servlet through the URL string. For example

script type="text/javascript" src="http://attacker.com/myservlet?name=myname"

Now the servlet can be invoked and process parameters and return the result back. There is a limitation however. It can only return Javascript code. You also have to set the content type as “application/x-javascript”. Just think of it as returning javascript code instead of html code. But there is a workaround to this limitation. Just like while returning html, if you had Javascript code, you would encapsulate in script tag, here, if you have to return html code, you can always return document .body .innerHTML = ‘html code’ or document .write(‘html code’). So your typical servlet would look like


public class myservlet
{
public void doGet(HttpServletRequest request, HttpServletResponse response)
{
response.setContentType(“application/x-javascript”);
PrintWriter out = response.getWriter();
String name = request.getParameter(“name”);
out.println(“document.body.innerHTML = ‘Welcome “ + name + “’;”);
out.close();
}
}


A JavaScript header is sent at the very beginning to inform the browser that it is receiving a JavaScript file. The final output of the servlet needs to be a valid Javascript file and must conform to Javascript syntax, servlet outputs a valid javascript code which replaces the content of the html page and displays “Welcome anurag”.
The other limitation, however, is that it cannot have an interactive session with the server side program. While loading the page, when the browser comes across the script tag, it goes to the URL mentioned in the src attribute and validates the incoming data as a valid javascript and executes it. The script tag is only executed once and after the entire page is loaded, it cannot call the server side program again.

Image Verification Utility for Form submission(Captcha)

Got from http://blog.jeffhaynie.us/image-verification-utility-for-form-submission.html
Thanks for the idea author.

Pasting the same below :
Image Verification Utility for Form submission
June 22nd, 2006 · No Comments

image verify screenshot Ever wanted one of those cool HTML form submission pages where you can make sure that only humans are submitting form data, and not machines (like spam bots)? Well, no you can have one. I created a simple Java utility class for generating the dynamic image in PNG format and then a simple servlet and web page for testing. You can download the source and demo here. Good luck!
Utility class

1: /**
2:  * Copyright (c) 2006 by Jeff Haynie
3:  *

4:  * Licensed under the Apache License, Version 2.0 (the “License”);
5:  * you may not use this file except in compliance with the License.
6:  *
7:  * You may obtain a copy of the License at
8:  * http://www.apache.org/licenses/LICENSE-2.0

9:  *
10:  * Unless required by applicable law or agreed to in writing,
11:  * software distributed under the License is distributed on an “AS IS” BASIS,
12:  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13:  * See the License for the specific language governing permissions and

14:  * limitations under the License.
15: */
16: package us.jeffhaynie.image;

17:
18: import java.awt.Color;
19: import java.awt.Font;

20: import java.awt.Graphics2D;
21: import java.awt.geom.AffineTransform;

22: import java.awt.image.BufferedImage;
23: import java.io.IOException;

24: import java.io.OutputStream;
25: import java.util.Random;

26: import java.util.UUID;
27:
28: import javax.imageio.ImageIO;

29:
30: /**
31:  * ImageVerification is a simple utility class for
32:  * creating an image verification PNG file that will
33:  * allow you to make sure that only a human can read

34:  * the alphanumeric values and enter them into a text
35:  * field during verification. 

36:  *
37:  * Make sure that when you can getVerificationCode

38:  * you don’t encode the value in the URL or inside the
39:  * HTML form - otherwise, this whole excerise is pointless
40:  * (dummy!).
41:  *
42:  * @author Jeff Haynie

43:  * @copyright Copyright (c) by Jeff Haynie. All Rights Reserved.
44:  */
45: public class ImageVerification
46: {

47:     private String value;
48:
49:     public ImageVerification (OutputStream out) throws IOException

50:     {
51:         this(50,120,out);

52:     }
53:     public ImageVerification (int height, int width, OutputStream out) throws IOException

54:     {
55:         BufferedImage bimage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);      

56:         Random rand=new Random(System.currentTimeMillis());

57:         Graphics2D g = bimage.createGraphics();
58:
59:         // create a random color

60:         Color color = new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255));

61:
62:         // the the background to the random color to fill the
63:         // background and make it darker
64:         g.setColor(color.darker());

65:         g.fillRect(0, 0, width, height);

66:
67:         // set the font
68:         g.setFont(new Font(“arial”,Font.BOLD,36));

69:
70:         // generate a random value
71:         this.value = UUID.randomUUID().toString().replace(“-”,“”).substring(0,5);

72:
73:         int w = (g.getFontMetrics()).stringWidth(value);

74:         int d = (g.getFontMetrics()).getDescent();

75:         int a = (g.getFontMetrics()).getMaxAscent();

76:
77:         int x = 0, y =0;

78:
79:         // randomly set the color and draw some straight lines through it
80:         for (int i = 0; i < x="0;" y="0;" i =" 0;" x =" width/2" y =" height/2" fontat =" new" xp =" x-2;" c="0;c

109:         {
110:             // apply a random radian either left or right (left is half since it’s too far back)
111:             int rotate = rand.nextInt(20);

112:             fontAT.rotate(rand.nextBoolean() ? Math.toRadians(rotate) : -Math.toRadians(rotate/2));

113:             Font fx = new Font(“arial”, Font.BOLD, 36).deriveFont(fontAT);

114:             g.setFont(fx);
115:             String ch = String.valueOf(value.charAt(c));

116:             int ht = rand.nextInt(3);
117:             // draw the string and move the y either up or down slightly

118:             g.drawString(ch, xp, y + (rand.nextBoolean()?-ht:ht));

119:             // move our pointer
120:             xp+=g.getFontMetrics().stringWidth(ch) + 2;

121:         }
122:         // write out the PNG file
123:         ImageIO.write(bimage, “png”, out);

124:
125:         // make sure your clean up the graphics object
126:         g.dispose();
127:     }

128:     /**
129:      * return the value to check for when the user enters it in. Make sure you
130:      * store this off in the session or something like a database and NOT in the
131:      * form of the webpage since the whole point of this exercise is to ensure that
132:      * only humans and not machines are entering the data.
133:      *

134:      * @return
135:      */
136:     public String getVerificationValue ()
137:     {

138:         return this.value;
139:     }
140: }

PMD integration -For better quality

To run the PMD on the entire source code, I used the below task:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


    
       
       
           rulesets/favorites.xml
           rulesets/logging-java.xml
           basic
           
           
               
           
       
   
 



--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
One need's to add the pmd jar's( pmd-4.0rc1 ) to the class path of ant as well to run the report on the complete source.

Source forge link : pmd.sourceforge.net

Javascript trouble shooting tools:

Javascript trouble shooting tools:

www.getFireBug.com à It is a powerful debugging tool for javascript. It is convenient just like eclipse debug. More details are in the website.

JSEclipse à Javascript editor plugin for eclipse . Helps in autocompletion, find the error in javascript. To use, extract the attached file, copy contents of plugins folder into ..\eclipse\plugins and features into ..\eclipse\features . Restart eclipse.

Simple usage details :

Right click on the JSP code enclosing the tag.

Note that this plugin marks the error in red. But it doesn’t show the actual cause of error(a limitation).

More details http://www.interaktonline.com/Products/Eclipse/JSEclipse/Overview/

Banging with cruiseControl

Cruise control,

I’ve done a cruise control setup . Subversion and cruisecontrol are integrated. My cruise control picks up the repository files from the subversion and builds the war file automatically for every 10(configurable) mins. Please follow the same steps. Use the binary mode file rather than using exe installation.

1) download cruisecontrol-bin-2.6.2.zip from http://sourceforge.net/project/showfiles.php?group_id=23523&package_id=16338&release_id=502915

2) set CVS_RSH=http://test.com/repos/Tree/TESTCMS – at cruisecontrol.bat

3) modify the project name in config.xml as TESTCMS

4) create TESTCMS header folder cruisecontrol-bin/projects/TESTCMS

5) Map the TESTCMS header with repository.(it will pull automatically all other files during ant build)

6) Set the interval in the config.xml

7) place the build.xml under TESTCMS

8) run the cruisecontrol-bin-2.6.2 >> cruisecontrol.bat

I am using the same build script where you are using for CMS. But I’ve modified only root directory as TESTCMS from cms
In addition to these, need to add the below in config.xml under tag:




Install the SVN.exe if not installed.
Change the project name in config.xml tag.
Create a folder with the project name in projects folder of CC

Deploy the webapp of CC in tomcat and control the Cruise.

A sample config is below:

<cruisecontrol>
<project name="TESTCMS">


<!-- Load environment variables -->
<property environment="env" toupper="true"/>

<!-- Commonly used directories -->
<property name="reportdir" value="${env.CCDIR}/report"/>

<!-- Defaults for email -->
<property name="buildmaster.email" value="test@test.com"/>
<property name="buildmaster.name" value="Buildmaster"/>

<listeners>
<currentbuildstatuslistener file="logs/${project.name}/status.txt"/>
</listeners>

<bootstrappers>
<svnbootstrapper localWorkingCopy="projects/${project.name}" />
</bootstrappers>

<modificationset quietperiod="30">
<svn localWorkingCopy="projects/${project.name}"/>
</modificationset>

<schedule interval="7200">
<ant anthome="apache-ant-1.6.5" buildfile="projects/${project.name}/build.xml"/>
</schedule>

<log>
<merge dir="projects/${project.name}/target/test-results"/>
</log>

<publishers>
<onsuccess>
<artifactspublisher dest="artifacts/${project.name}" file="D:\TESTRelease\sandeep\cruisecontrol-bin-2.6.2\projects\TESTCMS\pmd_report.html"/>
<artifactspublisher dest="artifacts/${project.name}" file="D:\TESTRelease\sandeep\cruisecontrol-bin-2.6.2\projects\cms\build\war\TESTCMS.war"/>


</onsuccess>
<htmlemail>
<always address="test@test.com"/>

<!-- <failure address="tommy@test.com"/> -->
</htmlemail>
</publishers>

<plugin name="svn" classname="net.sourceforge.cruisecontrol.sourcecontrols.SVN"/>
<plugin name="svnbootstrapper" classname="net.sourceforge.cruisecontrol.bootstrappers.SVNBootstrapper"/>

<plugin name="htmlemail"
buildresultsurl="http://172.16.152.126:7070/cruisecontrol/buildresults/${project.name}"
mailhost="IP adress of mail host"
returnaddress="${buildmaster.email}"
returnname="${buildmaster.name}"
subjectprefix="[BUILD ${project.name}]"
/>

</project>
</cruisecontrol>

Tips and traps:
cruisecontrol-bin-2.6.2. integrating with SVN may be tricky.
You need to install SVN client first. Note that the plugin provided by cruise control for
SVN just calls the SVN.exe file using exec call.
Initially the SVN checkout wont work. This is deu to a bug in the SVN plugin by cruise control. The bug is something related to characters in cmd parameter.
Work around is to do a manual checkout using svn.exe co <path> . Then onwards the cruise control rocks.

Another thing to note is to put the below in cruisecontrol.bat
set CVS_RSH=<path to SVN>

There seems to be a bug in this bat file also.Like single quote not compatible with XP..Be aware

One can integrate PMD with SVN just by adding the build task in build.xml. The artifact can be pointed by specifyin the destination

Welcome to the J2EE Jungle

Yes! It's a jungle out there... Piles and piles of stuff converging into newer and better species ..New creatures are evolving by merging together leaving out lot of people confused as to where to go what to use.. They end up searching through this jungle for better and sophisticated creature(s) which can do their job. First they need to tame it and then deploy it for their tasks. Well the problem is by the time they almost tame it, there is a better one. These beasts become better and better day by day... And you end up searching and searching .......googling all the time........ Species in the J2EE jungle are broadly classified as -Webby - Very beautiful ...eye candy + servers who serve them. -Business providers ---Mostly similar to donkeys.Work hard! Well they have little brains so we gotta tweak them with logica. -Model - These creatures take care of storing food stuff... :) They collect fruits and store it for use. Like a Bee colony. Very neatly managed.. These food are used by all other creatures classified above in one form or the other. :D Well you pick up the best working beasts from the above classification, store food and serve them. There are areas in the jungle which have evolved in such a way that they integrate all the above classified ones into a lovely place where work gets done easier and better. They have evolved and have become a seperate Klan - ....LifeRay... T