Struts2: <img src="${url}"/>

In case of specifying the url for the image in struts2, you can write as follows.

<s:iterator value="books" status="rowstatus">
<s:url id="url" value="%{bookImagePath[#rowstatus.index]}"/>
 <img src="${url}" alt="Book image" align="top"/>
</iterator>

ERROR JDBCExceptionReporter - Duplicate entry

By using mysql, I faced the followin error and here is the solution

2009-01-08 22:55:18,454  WARN JDBCExceptionReporter - SQL Error: 1062, SQLState: 23000
2009-01-08 22:55:18,454 ERROR JDBCExceptionReporter - Duplicate entry '268731' for key 1
2009-01-08 22:55:18,454 ERROR AbstractFlushingEventListener - Could not synchronize database state with sessi
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update

Close the session after transaction.commit().

transaction.commit();
session.flush();
session.close();

Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost

I faced the following error and here is the solution.

  ** BEGIN NESTED EXCEPTION **

java.io.EOFException
MESSAGE: Can not read response from server. Expected to read 4 bytes, read 2
bytes before connection was unexpectedly lost.

STACKTRACE:

java.io.EOFException: Can not read response from server. Expected to read 4
bytes, read 2 bytes before connection was unexpectedly lost. 

Comment the wait_timeout such as below.

#wait_timeout=30

SocketException: Too many open files

If you see the following error,

java.net.SocketException: Too many open files

Try to change the max open file value for the user

#check current value by calling
ulimit -a
#Set new max open file
ulimit -n 102400

as well as the OS

#Check current value
cat /proc/sys/fs/file-max
#Set the new max open file by adding the following 
vi /etc/sysctl.conf
--
fs.file-max = 49500
--

SQL Error: 0, SQLState: 08S01

If you see the such a error by using hibernate3, you need the following to avoid it.

JDBCExceptionReporter　SQL Error: 0, SQLState: 08S01

In hibernate.cfg.xml, write

<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">20</property>
<property name="c3p0.timeout">1800</property>
<property name="c3p0.max_statements">50</property>

Then create "c3p0.properties" in your root classpath folder and write

c3p0.testConnectionOnCheckout=true
c3p0.acquireRetryDelay=1000
c3p0.acquireRetryAttempts=1

Illegal mix of collations in MySQL

In case for having such a error in mysql using Hibernate or so.

java.sql.SQLException: General error message
from server: "Illegal mix of collations
 (utf8_general_ci,COERCIBLE) and 
(latin1_swedish_ci,IMPLICIT) for operation '='"

Add the following in my.cnf

[client]
default-character-set = utf8

[mysqld]
skip-character-set-client-handshake
default-character-set=utf8
character-set-server=utf8
init-connect=SET NAMES utf8

Apache2.2 : AuthUserFile Error

<Location /svn>
       DAV svn
       SVNParentPath "/var/svn"
       AuthzSVNaccessFile /var/svn/.htpasswd
       AuthType Basic
       AUthName "Dev Project"
       AuthUserFile /var/svn/.htpasswd
</Location>

I set the basic authentication such as above which ended up the below error.

# /etc/init.d/apache2 reload
Syntax error on line 64 of /etc/apache2/mods-enabled/dav_svn.conf:
Invalid command 'AuthUserFile', perhaps misspelled or defined by a module not included in the server configuration

Since below,

$ for i in /usr/lib/apache2/modules/*; do strings $i | grep -q -i AuthUser && echo $i; done
/usr/lib/apache2/modules/mod_authn_file.so
$ ls /etc/apache2/mods-available/authn_file.load
/etc/apache2/mods-available/authn_file.load

You need to do as follow,

$ sudo /usr/sbin/a2enmod authn_file
Module authn_file installed; run /etc/init.d/apache2 force-reload to enable.
$ /usr/sbin/apache2ctl configtest
Syntax OK

JBoss Setting

After the installation of JBoss, here is the know-how of its setting.

1) Heap size

$ sudo vim $JBOSS/bin/run.conf

JAVA_OPTS="-Xms128m -Xmx512m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000"
=>
JAVA_OPTS="-Xms512m -Xmx768m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000"

2) Port check

vim $JBOSS/server/default/deploy/jboss-web.deployer/server.xml

3) Transaction time out

vim $JBOSS/server/default/conf/jboss-service.xml

300
=>
150

4) Thread number

vim server/default/deploy/jboss-web.deployer/server.xml

maxThreads="250"
=>
maxThreads="200"

5) Log Output level by log4j

vim /opt/jboss-4.2.3.GA/server/default/conf/jboss-log4j.xml 
   <root>
     <priority value="WARN" />
      <appender-ref ref="CONSOLE"/>
      <appender-ref ref="FILE"/>
   </root>

Struts2 and Hibernate v3 Min. Lib.

Those are the minimum required libraries for Struts2 and Hibernate v3.

Struts2

-commons-logging
-freemaker
-ognl
-struts2-core
-xwork

JBoss

-hibernate3
-antlr
-comons-collection
-dom4j
-javassist
-jta
-slf4j-api

Log4J Log rotate

It's better to log rotate by Java side than using Linux/Unix logrotate.
This is the example for log4J v1.2x (The v1.3 development is stopped by the way.) series , "log4j.xml" file.

By using DailyRollingFileAppender, you can log rotate as the date base.

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
 <!--Definition of the File Appender -->
    <appender name="file" class="org.apache.log4j.DailyRollingFileAppender">
     <!-- Date pattern policy -->
        <param name="DatePattern" value=".yyyy-ww" />
      
      <param name="File" value="logs/hibernate.log"/>
      <!-- Log append -->
     <param name="Append" value="true" />
     
     <!-- Log layout -->
     <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" value="%d %5p %c{1} - %m%n" />
      </layout>
     
     <!-- Default log level -->
     <param name="threshold" value="info"/>
     
    </appender>
    
    <!--Console log appender -->
    <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
     <!-- Default log level -->
        <param name="threshold" value="info"/>
        <!-- log layout -->
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d %5p %c{1} - %m%n"/>
        </layout>
    </appender>

  <root>
    <appender-ref ref="stdout"/>
    <appender-ref ref="file"/>
  </root>
</log4j:configuration>

File code converting

After moving from Windows dev. environment to Linux, source file needs to be converted to UTF8 from Shift_JIS. It's done easily.

 find ./* -type f -name '*.java' -exec nkf -Luw --overwrite {} \;

Flv file convert

Flv file convert to music format

.flv to mp3

$ ffmpeg -i xxx.flv -vn -acodec aac -ab 128k -ac 2 -ar 44100 -y test.mp3

.flv to aac

$ ffmpeg -i xxx.flv -vn -acodec mp3 -ab 128k -ac 2 -ar 44100 -y test.mp3

.flv to mp4

$ ffmpeg -bitexact -y -i OLD_TOWN.flv -vcodec mpeg4 -s 320x240 -r 25 -b 480k -acodec aac -ac 2 
-ar 22050 -ab 69k out.mp4

To cut mp3 then

$ sudo apt-get install poc-streamer
#mp3cut [ -o outputfile ] [ -T title ] [ -A artist ] [ -N album-name ] 
[ -t [hh:]mm:ss[+ms]-[hh:]mm:ss[+ms] ] mp3file [[ -t … ] mp3file1 …]

$ mp3cut -o cut.mp3 -t 00:08-00:49 test.mp3 

Awstats for Ubuntu

awstats is log analyzer I use it for tomcat log analysis.

<Host name="localhost" appBase="webapps" >
        <Valve className="org.apache.catalina.valves.AccessLogValve"
        directory="logs" prefix="ich_access_log."
        suffix=".txt" pattern="combined" resolveHost="false" / >
</Host >

Setting for awstats

cp -r /usr/share/awstats/icon /var/www/awstats-icon
/usr/lib/cgi-bin/awstats.pl -config=hostname -update

Then access to :http://hostname/cgi-bin/awstats.pl?config=hostname

Edit cron

crontab -e
--
0 1 * * * /usr/lib/cgi-bin/awstats.pl -config=hostname -update

Firefox3 Plugins

I've been using Hardy 8.04 which implements Firefox3.0b5.
Still many of FF plug-ins are not supported for FF3. If you want to use it by any means.

1) about:config 
2) Choose New>Boolean. Then "checkCompatibility" to "false".
3) Choose New>Boolean. "checkUpdateSecurity" to "false".
4) Restart Firefox and done ;-)

Change the folder name in English

Change the default folder such as Music/Document etc. name in English.

LANG=C xdg-user-dirs-gtk-update

zshrc

mine

# Created by newuser for 4.3.4

export JAVA_HOME=/usr/lib/jvm/java-6-sun
export PATH=$PATH:/opt/apache-maven-2.0.8/bin

alias eclipse='/opt/eclipse/eclipse'
alias update='sudo apt-get update'
alias upgrade='sudo apt-get upgrade'
alias du="du -h"
alias df="df -h"
alias ps="ps -aux"

# For auto compinit
autoload -U compinit
compinit

# For prompt
PROMPT="%/%% "
PROMPT2="%_%% "
SPROMPT="%r is correct? [n,y,a,e]: "

# For title bar
case "${TERM}" in
kterm*|xterm)
    precmd() {
        echo -ne "\033]0;${USER}@${HOST%%.*}:${PWD}\007"
    }
    ;;
esac

# For history function
HISTFILE=~/.zsh_history
HISTSIZE=10000
SAVEHIST=10000
setopt hist_ignore_dups     # ignore duplication command history list
setopt share_history        # share command history data

# For History search shortcut
autoload history-search-end
zle -N history-beginning-search-backward-end history-search-end
zle -N history-beginning-search-forward-end history-search-end
bindkey "^P" history-beginning-search-backward-end
bindkey "^N" history-beginning-search-forward-end

# Editor vi mode
bindkey -v

# For remembering the previous folder
setopt auto_pushd

# No beep
setopt nolistbeep

# For auto-prediction function
autoload predict-on
predict-on

Ubuntu Gutsy Step1

I just bought Dell Inspiron 1720 for my private note PC.
I certainly decided to delete Vista and then install Ubuntu for the box.
This is step by step set up for my reminder.
I skip writing the way to add apt line or so as it is too easy procedure to forget.

*Sound - you need to install the following package to enable the sound

$ sudo apt-get install linux-backports-modules-generic

1) I suggest to visit here for your little preparation
http://easylinux.info/wiki/Ubuntu:Gutsy

2) Font installation

#Mplus
% sudo cp /usr/share/fonts/truetype/ipa/ipag.ttf .
% sudo fontforge -script m++ipa.pe
% sudo mkdir /usr/share/fonts/truetype/mplus
% sudo mv M*IPAG.ttf /usr/share/fonts/truetype/mplus/.
% sudo fc-cache -f -v /usr/share/fonts/truetype/mplus

#Mikacha for the same step

3) Then go to forum to see what you want to do.
http://ubuntuforums.org/

4) Adobe related s/w
Flash capability is important. Visit adobe page to download the flash player.

$ tar zvxf install_flash_player_9_linux.tar.gz 
$ cd install_flash_player_9_linux/
$ sudo ./flashplayer-installer 

--
Copyright(C) 2002-2006 Adobe Macromedia Software LLC.  All rights reserved.
Adobe Flash Player 9 for Linux
Adobe Flash Player 9 will be installed on this machine.
You are running the Adobe Flash Player installer as the "root" user.
Adobe Flash Player 9 will be installed system-wide.
Support is available at http://www.adobe.com/support/flashplayer/
To install Adobe Flash Player 9 now, press ENTER.
To cancel the installation at any time, press Control-C.
NOTE: Please exit any browsers you may have running.
Press ENTER to continue...
Please enter the installation path of the Mozilla, Netscape,
or Opera browser (i.e., /usr/lib/mozilla): /usr/lib/firefox

----------- Install Action Summary -----------
Adobe Flash Player 9 will be installed in the following directory:
Browser installation directory = /usr/lib/firefox
Proceed with the installation? (y/n/q): y
Installation complete.
Perform another installation? (y/n): n
Please log out of this session and log in for the changes to take effect.
The Adobe Flash Player installation is complete.

#Then PDF
$sudo aptitude install acroread acroread-plugins acroread-escript
$sudo aptitude install mozilla-acroread

--set at the first launch :: Edit -> Prefences -> Interne
 Browser Executable: /usr/bin/firefox
 libgtkembedmoz Folder: /usr/lib/firefox/ 

5) java capability

$ sudo apt-get install sun-java6-jre sun-java6-plugin
$ sudo update-java-alternatives -s java-6-sun
$ sudo vim /etc/jvm
--
#Add the following line in the top of the file
/usr/lib/jvm/java-6-sun

MySQL5 character set

All you need to edit my.cnf in order not to write the command like "set name xxx" everytime you restart the service.

[client]
default-character-set = utf8

[mysqld]
skip-character-set-client-handshake
default-character-set = utf8
character-set-server = utf8
collation-server = utf8_general_ci
init-connect = SET NAMES utf8

[mysqldump]
default-character-set = utf8

[mysql]
default-character-set = utf8

In order to check the charset

mysql> shwo variables like 'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | latin1                     |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

#Then set charset
mysql>set character_set_database=utf8
mysql> show variables like 'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

Maven2 deploy to other server

Create file settings.xml under .m2

<?xml version='1.0' encoding='utf-8' ?>
<settings>
  <servers>
    <server>
      <id>scp-repository</id>
      <username>cavalier</username>
      <privateKey>C:\Program Files\PuTTY\auth\id_rsa</privateKey>
      <passphrase>xxxxxx</passphrase>
      <filePermissions>664</filePermissions>
      <directoryPermissions>775</directoryPermissions>
    </server>
  </servers>
</settings>

Then add the following to pom.xml

<distributionManagement>
 <repository>
 <id>scp-repository</id>
 <url>scp://192.168.0.xx/home/cav/repository</url>
 </repository>
</distributionManagement>

maven2 java version

You might need to specify the compile java version by using generics etc in pom.xml file.

<project>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.6</source>
          <target>1.6</target>
          <encoding>UTF-8</encoding>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>