Validation groups can be used to control which rules validation rules to run. A validation group can be identified by any Java interface (not class!). Multiple validation groups may be specified when validating. In this example, I added a validation group named MyValidationGroup ( src/main/java/com/example/MyValidationGroup.java in Maven project): package com.example; public interface MyVal... and added a @Size rule for a person's name, because my database can only store up to 15 characters for a person's name: package com.example; import javax.validatio... Now validate Person with a JUnit test ( src/test/java/com/example/TestPersonWithGroup.java in Maven project): package com.example; import java.util.Set; ... Test with " mvn clean test ". The rules where groups is not specified, which belong to the javax.validation.groups.Default group, are not executed with these tests.

Step 1: Repackage a web app as EAR A Java EE application is a multimodule Maven project. At the very least you'll need to package a WAR and an EAR. To get started, I'll simply re-package the simple webapp as an EAR. Create a directory named javaee-app Copy the webapp from here to javaee-app . Rename struts1app to webapp . Create pom.xml under javaee-app : <project> <modelVersion>4.0.0</modelVersion>... Create a directory named ear under javaee-app . Create pom.xml under ear : <project> <modelVersion>4.0.0</modelVersion>... Modify pom.xml in the webapp directory so that it looks like this: <project> <modelVersion>4.0.0</modelVersion> ... Build with " mvn package " in the javaee-app directory. You can see that ear-1.0.ear is successfully generated in javaee-app/ear/target . Maven successfully resolves dependencies between the sub-projects....

This is a simple example to demonstrate the templating power of JSF facelets. If you've used struts tiles before, you'll recognize the simplicity of templating with facelets. I've stripped out everything else except the pages themselves, just to put our focus on facelets. This is a Maven based project, and you need Tomcat (or any servlet container) to run the resulting webapp. To begin with this is the list of files: ./pom.xml ./src/main/webapp/home.xhtml ./src... I left faces-config.xml in there for completeness sake, it may not be needed. The Maven POM ( pom.xml ): <?xml version="1.0" encoding="UTF-8"?> <project... Web app configuration ( WEB-INF/web.xml ): <?xml version="1.0" encoding="UTF-8"?> <web-app... Empty WEB-INF/faces-config.xml : <?xml version="1.0" encoding="UTF-8"?> <!-- Thi... index.jsp is simply a redirect to home.jsf : <% response.sendRedirect("home.jsf"); %>...

This procedure sets up an IPSec vpn server on Linux with Preshared Key (PSK) using Openswan . Install Openswan: # yum install openswan Edit /etc/ipsec.conf . This is about the minimum needed to run IPSec server. Instead of running L2TP on port 1701, I'm running TCP on port 8080 so that I can test the setup with nc later. # /etc/ipsec.conf - Openswan IPsec configurati... Edit /etc/ipsec.secrets . # # Preshared key for clients connecting from a... Start IPSec: # /etc/init.d/ipsec start Check status: # ipsec auto --status Monitor IPSec log: # less /var/log/secure If IPSec is running KLIPS, you should see a new nic ( ipsec0 ). There's no ipsec0 if IPSec is running NETKEY. # ifconfig eth0 Link encap:Ethernet HWadd...

VirtualBox creates/uses a network adapter named vboxnet0 on the host, when a VM network adapter is connected as "host-only". As the VM starts, VirtualBox assigns the IP address 192.168.56.1 to vboxnet0 on the host. The VM DHCP client grabs the IP address 192.168.56.101 from the VirtualBox DHCP server. Connectivity is limited between the VM and the host - unless you configure NAT and IP forwarding on the host. For OpenWRT, if the DHCP client is not started automatically: #/sbin/udhcpc -i br-lan -p /var/run/udhcpc.pid -s ...

Click Project -> Properties Select "Builders" Click "New", select "Ant Builder", click "OK" Select the Buildfile, set the Base Directory Set targets You may or may not want the default "Java Builder". Uncheck it if you don't want to run the default builder.

A security manager is automatically installed when you run an applet, but not so when you run an application. Setting the java.security.manager property enables the default Security Manager for the application. For example, you can bind to a "privileged" port without security manager: $ java SocketBind localhost:83 Binding to local... With security manager, it fails: $ java -Djava.security.manager SocketBind loca...

The DHCP client packaged with BusyBox is udhcpc . It negotiates a lease with the DHCP server and executes a script when it is obtained or lost. There are four possible arguments to this script: deconfig : The script should put the interface in an up but deconfigured state. bound : The script should configure the interface and set any other relevant parameters. renew : This is used when a lease is renewed. IP address does not change but other parameters may change. nak : This happens when a NAK packet is received from the DHCP server. Network parameters are passed to the script via environment variables. Ubuntu documents that the default script is at /etc/udhcpc/default.script . For OpenWRT, it is located at /usr/share/udhcpc/default.script ....

Fedora/Redhat List current status (for httpd): # chkconfig --list httpd Warning: this works only when one of /etc/rc runlevel .d/ K NN name or /etc/rc runlevel .d/ S NN name exists. It exports wrong status when both K and S scripts exist (in which case the status should be enabled). Enable sshd for run levels 2, 3, 5: # chkconfig --level 2,3,5 sshd on Disable sshd for run levels 2, 3, 5: # chkconfig --level 2,3,5 sshd off By default, the on and off options affect only runlevels 2, 3, 4, and 5. Debian/Ubuntu Add apache2 with defaults : # update-rc.d apache2 defaults If defaults is used then update-rc.d will make links to start the service in runlevels 2, 3, 4, 5 and to stop...

In Linux shell (bash & ksh), executing " set -m " turns on job control . This option is on by default for interactive shells . Background processes run in a separate process group and a line containing their exit status is printed upon their completion.