Design patterns in jdk. Nice Post.

http://www.briandupreez.net/2010/11/design-patterns-in-jdk.html

Maven

UPDATE VERSION NUMBERS IN MULTI MODULE PROJECT:- mvn -e release:update-versions -DautoVersionSubmodules=true

View Super POM via effective-pom:- mvn help:effective-pom
Maven has:- Lifecycles, Phases, Plugins and Goals.

mvn deploy : deploy is a lifecycle. Which has phases verification, compilation, testing and packaging.

Executing phase or goal: mvn compile:compile jar:jar

Prepare your project to go offline: mvn dependency:go-offline

Go offline: mvn -o

Help for plugin:- mvn help:describe –D
Ex:- mvn help:describe -Dplugin=help -Dfull

Help for profiles:- mvn help:active-profiles

List hierarchy of dependencies:- mvn dependency:tree

List dependencies in alphabetic form:- mvn dependency:resolve

List plugin dependencies in alphabetic form:- mvn dependency:resolve-plugins

Analyze dependencies and list any that are unused, or undeclared.:- mvn dependency:analyze

Printing exception stack trace for a goal:- mvn -e

Output debugging info for a goal:- mvn -X

Debugging a unit test:- mvn test -Dmaven.surefire.debug

Manual Profile activation:- mvn –P YourProfile

Release using maven:- mvn release:perform

Creating archetype from project:- mvn archetype:create-from-project

wget with basic authentication.

Here's how you download a file from internet which is secured by basic authentication. Replace myusername, mypassword with your own username and password.

wget http://download_file --http-user=myusername --http-passwd=mypassword

Hudson init script for Ubuntu 9.04

Hudson init script for ubuntu 9.04. This is available on hudson's website too.

http://wiki.hudson-ci.org/display/HUDSON/Installation+and+Execution

This is what worked for me. The one hudson website is for linux. This you can use as is without modifications (except for "RUN_AS") on ubuntu

#!/bin/sh

DESC="Hudson CI Server "
NAME=hudson
PIDFILE=/var/run/$NAME.pid
RUN_AS=sysadm

d_start() {
 start-stop-daemon --start --quiet --background -m --pidfile $PIDFILE --chuid $RUN_AS --exec /usr/bin/java -- -Dhudson.scm.CVSSCM.skipChangeLog=true -jar /opt/hudson/hudson.war
}

d_stop() {
 start-stop-daemon --stop --quiet --pidfile $PIDFILE
 if [ -e $PIDFILE ]
  then rm $PIDFILE
 fi
}

case $1 in
 start)
 echo -n "Starting $DESC: $NAME "
 d_start
 echo "."
 ;;
 stop)
 echo -n "Stopping $DESC: $NAME "
 d_stop
 echo "."
 ;;
 restart)
 echo -n "Restarting $DESC: $NAME "
 d_stop
 sleep 1
 d_start
 echo "."
 ;;
 *)
 echo "usage: $NAME {start|stop|restart}"
 exit 1
 ;;
esac

exit 0

SSH without Password

I got information from this site

http://www.csua.berkeley.edu/~ranga/notes/ssh_nopass.html

SSH Without a Password

The following steps can be used to ssh from one system to another without specifying a password.
Notes:

* The system from which the ssh session is started via the ssh command is the client.
* The system that the ssh session connects to is the server.
* These steps seem to work on systems running OpenSSH.
* The steps assume that a DSA key is being used. To use a RSA key substitute 'rsa' for 'dsa'.
* The steps assume that you are using a Bourne-like shell (sh, ksh or bash)
* Some of this information came from:
http://www.der-keiler.de/Mailing-Lists/securityfocus/Secure_Shell/2002-12/0083.html

Steps:

1.

On the client run the following commands:

$ mkdir -p $HOME/.ssh
$ chmod 0700 $HOME/.ssh
$ ssh-keygen -t dsa -f $HOME/.ssh/id_dsa -P ''

This should result in two files,

$HOME/.ssh/id_dsa (private key) and 
$HOME/.ssh/id_dsa.pub (public key).

2.

Copy $HOME/.ssh/id_dsa.pub to the server.

3.

On the server run the following commands:

$ cat id_dsa.pub >> $HOME/.ssh/authorized_keys2
$ chmod 0600 $HOME/.ssh/authorized_keys2

Depending on the version of OpenSSH the following commands may also be required:

$ cat id_dsa.pub >> $HOME/.ssh/authorized_keys
$ chmod 0600 $HOME/.ssh/authorized_keys

An alternative is to create a link from authorized_keys2 to authorized_keys:

$ cd $HOME/.ssh && ln -s authorized_keys2 authorized_keys

4.

On the client test the results by ssh'ing to the server:

$ ssh -i $HOME/.ssh/id_dsa server

5.

(Optional) Add the following $HOME/.ssh/config on the client:

Host server
IdentityFile ~/.ssh/id_dsa

This allows ssh access to the server without having to specify the path to the id_dsa file as an argument to ssh each time.

HUDSON: THINGS TO REMEMBER [Skip Change Log]

While starting hudson use:

java -Dhudson.scm.CVSSCM.skipChangeLog=true -jar hudson.war

This makes sure that hudson skips computing change log. Computing change log option is
slow for one thing and caused a lot of problems while I was setting it up in our projects.

Carnatic Music Website.

http://www.ecse.rpi.edu/Homepages/shivkuma/personal/music/index.html

Professor Shiv Kumar Kalyanaraman's carnatic music archive. Wonderful website for carnatic music.

Move sqlserver tables to dbo user

SELECT 'ALTER SCHEMA dbo TRANSFER ' + SCHEMA_NAME(schema_id) + '.' + name
FROM sys.tables
WHERE schema_id != SCHEMA_ID('dbo');

Starting JavaDB (Derby) in glassfish.

I was following sahoo's Blog for creating an enterprise application with ejb3.0.
http://weblogs.java.net/blog/ss141213/archive/2005/12/using_java_pers.html

Ran into problem since JavaDB isn't started automatically when glassfish starts.

Error was "Error connecting to server localhost on port 1527 with message Connection refused: connect."

Solution:

You will have to issue below command to start derby database:

GlassFishHome/bin/> asadmin start-database

Hope this helps someone having similar issues.

Samba File Sharing Ubuntu

SSH server is disabled by default in ubuntu. From package manager select & install ssh-server.

Samba File Sharing:

Setup up username & password:
smbpasswd -a
you'll be prompted to set the password.


Restart Samba service to take effect: [Just for good measure]
sudo /etc/init.d/samba restart