[Solved] Nginx - error: HTTP rewrite module requires the PCRE library

Nginx $ ./configure: error: the HTTP rewrite module requires the PCRE library. While trying to install Nginx server using the source distribution, "./configure" command failed on CentOS 6.7 with below error message. It complains that PCRE library is not available on the system.

./configure: error: the HTTP rewrite module requires the PCRE library.
You can either disable the module by using 
--without-http_rewrite_module option, or 
install the PCRE library into the system, 
or build the PCRE library statically from 
the source with nginx by using --with-pcre=<path> option.

Solution

You can install this library either via command line or GUI.

Resolve via Command line

yum install pcre-devel

Resolve via GUI

Go to "System" -> "Administration" -> "Add/Remove Software" as shown below.

Then search for "pcre-devel", select "Development files for pcre" and install by clicking "Apply" as shown below.

After that, you can rerun the "./configure" command to continue installing Nginx 1.12.1 server.
Hope this helps.

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[Eclipse] Exporting & Importing Launch configurations

Many Eclipse "Launch Configuration" created has so much details; OSGi configurations for instance. So there arises a requirement of exporting the launch configurations and later importing them into other Eclipse workspaces. Interestingly, Eclipse has an import/export feature for "Launch Configuration"; which is quite simple but handy. I believe some software developers are not taking the advantage of this.

Here are the steps to follow.

1. Exporting Configurations

First you need to select:
  File -> Export...
Then select:
  Run/Debug -> Launch Configurations

Then you will see a view with all available launch configurations as shown below. You can select the configurations you need to export. You need a provide a location to store the exported configurations.

Each configuration will be saved into separate XML files, but with the extension as ".launch".

2. Importing Configurations

Similar to export, first you need to select:
  File -> Import...
Then select:
  Run/Debug -> Launch Configurations

Then you will see a view where you can select a directory with ".launch" files. When that folder is selected, available launch configurations will be displayed in the UI; so that you can select which ones to be imported as shown below.

3. Sample .launch file

Below is the exporter file for the OSGi launch configuration we created for Eclipse Kepler 4.3.1.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<launchConfiguration type="org.eclipse.pde.ui.EquinoxLauncher">
    <booleanAttribute key="append.args" value="true"/>
    <booleanAttribute key="automaticAdd" value="true"/>
    <booleanAttribute key="automaticValidate" value="false"/>
    <stringAttribute key="bootstrap" value=""/>
    <stringAttribute key="checked" value="[NONE]"/>
    <booleanAttribute key="clearConfig" value="false"/>
    <stringAttribute key="configLocation" value="${workspace_loc}/.metadata/.plugins/org.eclipse.pde.core/Multi-Management-App"/>
    <booleanAttribute key="default" value="true"/>
    <booleanAttribute key="default_auto_start" value="true"/>
    <intAttribute key="default_start_level" value="4"/>
    <booleanAttribute key="includeOptional" value="true"/>
    <booleanAttribute key="org.eclipse.jdt.launching.ATTR_USE_START_ON_FIRST_THREAD" value="true"/>
    <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>
    <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-os ${target.os} -ws ${target.ws} -arch ${target.arch} -nl ${target.nl} -consoleLog -console"/>
    <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
    <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Declipse.ignoreApp=true -Dosgi.noShutdown=true"/>
    <stringAttribute key="pde.version" value="3.3"/>
    <booleanAttribute key="show_selected_only" value="true"/>
    <stringAttribute key="target_bundles" value="org.apache.felix.gogo.command@default:default,org.apache.felix.gogo.runtime@default:default,org.apache.felix.gogo.shell@default:default,org.eclipse.equinox.console@default:default,org.eclipse.osgi@-1:true"/>
    <booleanAttribute key="tracing" value="false"/>
    <booleanAttribute key="useCustomFeatures" value="false"/>
    <booleanAttribute key="useDefaultConfigArea" value="true"/>
    <stringAttribute key="workspace_bundles" value="com.digizol.osgi.multiservice.english@default:default,com.digizol.osgi.multiservice.sinhala@default:default,com.digizol.osgi.multiservice@default:default,com.digizol.osgi.baseservice@default:default"/>
</launchConfiguration>

Hope this helps you.

[Eclipse] org.osgi.framework.BundleException: Could not find bundle: org.eclipse.equinox.console

With latest Eclipse Kepler 4.3.1 SR1, I tried to run one of my older OSGi projects. Earlier this project was running smoothly with Eclipse Indigo (3.7.1).

However, when I tried to execute it via Eclipse Kepler version as a "OSGI Framework" configuration; I was surprised since it showed an exception as org.osgi.framework.BundleException: Could not find bundle: org.eclipse.equinox.console .

Below is the complete stack-trace.

!SESSION date time -----------------------------------------------
eclipse.buildId=unknown
java.version=1.6.0_26
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86, WS=gtk, NL=en_US
Command-line arguments:  -dev file:$Location/dev.properties -os linux 
                         -ws gtk -arch x86 -consoleLog -console

!ENTRY org.eclipse.osgi 4 0 date time
!MESSAGE Could not find bundle: org.eclipse.equinox.console
!STACK 0
org.osgi.framework.BundleException: Could not find bundle: org.eclipse.equinox.console
 at org.eclipse.osgi.framework.internal.core.ConsoleManager.checkForConsoleBundle(ConsoleManager.java:211)
 at org.eclipse.core.runtime.adaptor.EclipseStarter.startup(EclipseStarter.java:298)
 at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:177)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:636)
 at org.eclipse.equinox.launcher.Main.basicRun(Main.java:591)
 at org.eclipse.equinox.launcher.Main.run(Main.java:1450)
 at org.eclipse.equinox.launcher.Main.main(Main.java:1426)

Solution

A quick look into the details revealed that the default shell of Eclipse has been moved to "Apache Felix Gogo"; so the necessary bundles must be added to the "Run Configuration" before running. Followings are the four bundled that you need to select from the list.

org.apache.felix.gogo.command_0.10.0v<version>.jar
org.apache.felix.gogo.runtime_0.10.0v<version>.jar
org.apache.felix.gogo.shell_0.10.0v<version>.jar
org.eclipse.equinox.console_1.0.100<version>.jar

After adding these as shown in the above diagram, the program runs smoothly.

For more details on the changes on OSGi shell, please refer here.

OSGi Console of Eclipse Kepler 4.3.1

Eclipse IDE is developed based on OSGi plugin architecture, but I had not seen the list of OSGi bundles that are used in my Eclipse installation. Today I noticed that there is a way to find the list of bundled used, and it is quite simple. So I thought of sharing it with you.

I am running Eclipse version 4.3.1 (JEE Kepler). First we need to open the OSGi console of the running Eclipse instance. For that we need to open up the 'Console view' first via:

Window -> Show view -> Console

Then you need to select "Host OSGi Console" on the sub-toolbar in this Console view as shown in the image below.

As soon as you go to this console view, you will see below WARNING, which is quite OK since our intention is also to connect to the running instance of Eclipse.

WARNING: This console is connected to the current running instance of Eclipse!
osgi>

If you are already familiar with OSGi console in OSGi software development, then most likely you know how to find details about the plugins. However even if you are new to OSGi, no need to worry. You simple have to enter "ss" command in this console to see the list of bundles with id and state. I got a list of 822 plugins and below is a trimmed down version of the output I received.

WARNING: This console is connected to the current running instance of Eclipse!
osgi> ss
"Framework is launched."


id State       Bundle
0 ACTIVE      org.eclipse.osgi_3.9.1.v20130814-1242
1 ACTIVE      org.eclipse.equinox.simpleconfigurator_1.0.400.v20130327-2119
2 RESOLVED    ch.qos.logback.classic_1.0.7.v20121108-1250
             Fragments=525
3 RESOLVED    ch.qos.logback.core_1.0.7.v20121108-1250
4 RESOLVED    ch.qos.logback.slf4j_1.0.7.v20121108-1250
             Master=817
5 ACTIVE      com.ibm.icu_50.1.1.v201304230130
6 RESOLVED    com.jcraft.jsch_0.1.46.v201205102330
7 RESOLVED    com.ning.async-http-client_1.6.5.20130531-2315
8 RESOLVED    com.sun.el_2.2.0.v201303151357
9 RESOLVED    com.sun.syndication_0.9.0.v200803061811
10 RESOLVED    java_cup.runtime_0.10.0.v201005080400
11 RESOLVED    javaewah_0.5.6.v201307211000
12 RESOLVED    javax.activation_1.1.0.v201211130549
13 RESOLVED    javax.annotation_1.1.0.v201209060031
14 RESOLVED    javax.el_2.2.0.v201303151357
15 RESOLVED    javax.inject_1.0.0.v20091030
16 RESOLVED    javax.jws_2.0.0.v201005080400
17 RESOLVED    javax.mail_1.4.0.v201005080615
18 RESOLVED    javax.persistence_2.1.0.v201304241213
19 RESOLVED    javax.servlet_3.0.0.v201112011016
20 RESOLVED    javax.servlet.jsp_2.2.0.v201112011158
21 RESOLVED    javax.wsdl_1.6.2.v201012040545
22 RESOLVED    javax.wsdl_1.5.1.v201012040544
23 RESOLVED    javax.xml_1.3.4.v201005080400
24 RESOLVED    javax.xml.bind_2.1.9.v201005080401
25 RESOLVED    javax.xml.rpc_1.1.0.v201209140446
26 RESOLVED    javax.xml.soap_1.2.0.v201005080501
27 RESOLVED    javax.xml.stream_1.0.1.v201004272200
28 RESOLVED    javax.xml.ws_2.1.0.v200902101523
29 RESOLVED    net.sourceforge.lpg.lpgjavaruntime_1.1.0.v201004271650
30 RESOLVED    org.apache.ant_1.8.4.v201303080030
31 RESOLVED    org.apache.axis_1.4.0.v201005080400
32 RESOLVED    org.apache.batik.css_1.6.0.v201011041432
33 RESOLVED    org.apache.batik.util_1.6.0.v201011041432
34 RESOLVED    org.apache.batik.util.gui_1.6.0.v201011041432
35 RESOLVED    org.apache.bcel_5.2.0.v201005080400
36 RESOLVED    org.apache.commons.codec_1.4.0.v201209201156
37 RESOLVED    org.apache.commons.collections_3.2.0.v2013030210310
38 RESOLVED    org.apache.commons.discovery_0.2.0.v201004190315
39 RESOLVED    org.apache.commons.httpclient_3.1.0.v201012070820
40 RESOLVED    org.apache.commons.io_2.0.1.v201105210651
41 RESOLVED    org.apache.commons.lang_2.6.0.v201205030909
42 RESOLVED    org.apache.commons.logging_1.1.1.v201101211721
43 RESOLVED    org.apache.commons.logging_1.0.4.v201101211617
44 RESOLVED    org.apache.commons.net_3.2.0.v201305141515
45 ACTIVE      org.apache.felix.gogo.command_0.10.0.v201209301215
46 ACTIVE      org.apache.felix.gogo.runtime_0.10.0.v201209301036
47 ACTIVE      org.apache.felix.gogo.shell_0.10.0.v201212101605
48 RESOLVED    org.apache.httpcomponents.httpclient_4.1.3.v201209201135
49 RESOLVED    org.apache.httpcomponents.httpcore_4.1.4.v201203221030
50 RESOLVED    org.apache.jasper.glassfish_2.2.2.v201205150955
51 RESOLVED    org.apache.log4j_1.2.15.v201012070815
52 RESOLVED    org.apache.lucene.analysis_3.5.0.v20120725-1805
53 RESOLVED    org.apache.lucene.core_3.5.0.v20120725-1805
54 RESOLVED    org.apache.velocity_1.5.0.v200905192330
55 RESOLVED    org.apache.ws.commons.util_1.0.1.v20100518-1140
56 RESOLVED    org.apache.wsil4j_1.0.0.v200901211807
57 RESOLVED    org.apache.xalan_2.7.1.v201005080400
58 RESOLVED    org.apache.xerces_2.9.0.v201101211617
59 RESOLVED    org.apache.xml.resolver_1.2.0.v201005080400
60 RESOLVED    org.apache.xml.serializer_2.7.1.v201005080400
61 RESOLVED    org.apache.xmlrpc_3.0.0.v20100427-1100
62 STARTING    org.eclipse.ant.core_3.2.500.v20130402-1746
63 STARTING    org.eclipse.ant.launching_1.0.300.v20130514-1341
64 STARTING    org.eclipse.ant.ui_3.5.400.v20130514-1341
65 STARTING    org.eclipse.compare_3.5.401.v20130709-1308
66 STARTING    org.eclipse.compare.core_3.5.300.v20130514-1224
67 RESOLVED    org.eclipse.core.commands_3.6.100.v20130515-1857

...

818 RESOLVED    org.sonatype.m2e.mavenarchiver_0.15.0.201207090125-signed-20130612210623
819 RESOLVED    org.uddi4j_2.0.5.v200805270300
820 RESOLVED    org.w3c.css.sac_1.3.1.v200903091627
821 RESOLVED    org.w3c.dom.smil_1.0.0.v200806040011
822 RESOLVED    org.w3c.dom.svg_1.1.0.v201011041433
osgi> 

If you are interested in finding further details about these OSGi bundles, you can enter 'help' in the OSGi console and find the list of commands to try out.

[Ubuntu] Multiple launchers for each individual Eclipse installation

I have multiple Eclipse versions installed in my Ubuntu 12.04, so I wanted to have separate launcher icons in Launchpad. However I noticed it is not possible to create launch icons simply using:
"Right click -> Lock to Launcher" approach since the same launcher icon is used for all Eclipse installations; simply said there will be only one launcher icon for all Eclipse installations. 

It is quite easy to create multiple launcher icons for multiple installations. Below is the 4 steps you need to follow.

1. Create <eclipse-name>.desktop files for each installation

I created eclipse-jee-kepler.desktop file inside Kepler Eclipse installation folders, but you use any preferred location.

2. Update <eclipse-name>.desktop file with information

For "Eclipse JEE Kepler" installation, add the below content to eclipse-jee-kepler.desktop. You will have to change the path to the executable eclipse file.

[Desktop Entry]
Version=4.3.1
Name=Eclipse JEE Kepler
Comment=Eclipse JEE Kepler
Exec=/<path>/eclipse-jee-kepler-SR1-linux-gtk/eclipse
Icon=/<path>/eclipse-jee-kepler-SR1-linux-gtk/eclipse.ico
StartupNotify=false
Terminal=false
Type=Application
Categories=Development

You can create an eclipse.ico file to be displayed in the Launchpad yourself. As displayed here, I have created a simple file for my usage.

3. Grant permission to execute

Right click on this eclipse-jee-kepler.desktop file and select "Properties". Then go to the "Permissions" tab and select execute permission as shown in the image.

4. Run the eclipse installation

You can double click on the eclipse-jee-kepler.desktop file to start your eclipse installation. When this eclipse installation is started, the provided eclipse.ico will be displayed in the Launchpad. Now you can create a launch icon simply using "Right click -> Lock to Launcher".

Finally...

For each of your eclipse installations, you can create separate files with above 4 steps; then replace the property values to match with each eclipse installations (including a separate .ico).

If you are interested in finding more information about Unity Launchers and Desktop files, you can refer here.

[Log4j] How to integrate with your Java project

This is a quick guide on how to use log4j in your Java project. This task requires only five simple steps listed below. Each of these step is explained in details below.

1. Set up the project with log4j
2. Create log4j.properties file
3. Write a class to record log messages
4. Compile and run program
5. Check the log messages

1. Set up the project with log4j

As the first step, let's download the log4j 1.2.17 latest archive (tar or zip). When you extract the archive, log4j-1.2.17.jar file is available in the root of the directory.

Let's create a new project named say log4j-helloworld and copy the log4j-1.2.17.jar into a folder named lib inside the project.

2. Create log4j.properties file

Next task is to create a log4j.properties file (shown below) inside the project folder. This file is the configuration file that provides how, where, which etc instructions on generating log messages.

# root level configurations
log4j.rootLogger=INFO,console,file

# configuration for console outputs
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout

# configuration for file output (into a file named messages.log)
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=messages.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout

# threshold for file output
log4j.appender.file.Threshold=ERROR

3. Write a class to record log messages

Let's write a simple class named Main (in src folder) with a main method to generate some log statements. Logger is added to the class as an attribute and used to write logs of different levels like debug, info and error.

package com.digizol.log4j.helloworld;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

public class Main {

    private static Logger log = Logger.getLogger(Main.class);

    public static void main(String[] args) {

        log.debug("This is debug method");
        log.info("This is info method");
        log.error("This is error method");

        log.log(Level.DEBUG, "This is debug from Level.DEBUG");
        log.log(Level.INFO, "This is info from Level.INFO");
        log.log(Level.ERROR, "This is error from Level.ERROR");

    }
}

4. Compile and run program

If you compile and run from command line, followings are the commands. Make sure to create classes folder inside project for generated class files before executing the commands.

# compile
javac -cp lib/log4j-1.2.17.jar -d classes -sourcepath src src/com/digizol/log4j/helloworld/Main.java

# run
java -cp lib/log4j-1.2.17.jar:./classes:./ com.digizol.log4j.helloworld.Main

If you are using an IDE like Eclipse, you can simply add log4j jar file into the build path before compiling. When running the Main class, you need to give the path to log4j.properties file in run configuration.

5. Check the log messages

In the Main class, we have added two debug level messages. However the rootLogger is configured in INFO level in log4j.properties file, so none of the debug level log messages are expected as outputs.

Console output as as below.

This is info method
This is error method
This is info from Level.INFO
This is error from Level.ERROR

Console has received both INFO and ERROR log messages, but not DEBUG.

However messages.log file has received only the ERROR level log messages as below.

This is error method
This is error from Level.ERROR

This is because the Threshold level of the file logging appender is set to ERROR which overrides the rootLogger configuration.

Hope this helps you to start using log4j in your next project. I have added this project here for your references.

[Ubuntu] DeVeDe generated DVD menus not working

DeVeDe is a popular software for DVD creation, and I am using 3.21.0 version of that on Ubuntu 12.04 to generate DVDs from different files of .avi, .mpg and .mp4 types. However after the upgrade to Ubuntu 12.04, I was facing issues with the menus of generated DVD. Recently, I noticed that this is due to an incompatibility issue with ffmpeg solution provided by Ubuntu (detailed bug is found here).

Simplest workaround for this issue is to avoid the use of ffmpeg, and interestingly DeVeDe provides an option to do this.

Go to "Edit -> Preferences"

then uncheck "Use FFMPEG instead of Mencoder" as shown in the below image.

That setting will resolve this problem.

Thunderbird: Search by Attachment Name

Finding emails which included had a particular attachment is really important. Last week I happened to digg through my email box to find a number of emails that contained a particular document as an attachment. The only information I know about those emails is; those contained this particular attachment. So how can I find the email?

It is quite simple; since the filename is already known, search box on top right-hand side can be used. As shown in the below image, you need to type the filename inside inverted comma.

In this example, I am searching for a file named "Digizol.com Thunderbird Article.doc".

To summarize, three simple steps are;
1. Press 'Ctrl + k'
2. Type filename inside inverted commas
3. Press Enter

Hope this helps.

Subversion 1.7 Released - Under Apache Software Foundation

Subversion 1.7, first feature release after moving to Apache Software Foundation is announced. Starting from this, Subversion will be released under Apache License, version 2 instead of the modified Apache license used by Tigris.

Interesting features

One single .svn folder

This is the most interesting feature for us. In Subversion 1.7 meta data will be stored into a single location at the root directory. As you are aware, currently there are .svn folders inside each and every folder of the working copy of your project. Instead of that there will be just one .svn directory in the root of the working copy.

New Command: svn patch

In Subversion 1.7 a new sub command is introduced named "patch" (i.e: svn patch) which can be used to apply patch files to a working copy. This command supports newly created files as well as deleted files.

Compatibility with 1.6

Older clients and servers will work fine with 1.7 even though new features will not be functional.

Download distributions

Distributions can be downloaded from following locations.

• subversion-1.7.0.zip
• subversion-1.7.0.tar.gz
• subversion-1.7.0.tar.bz2

Related Articles

• Attempted to lock an already-locked dir: Subversion issue
• svnadmin create a new empty project repository in subversion (svn) in Linux

Firefox Address (Location) Bar Hidden or Missing

Firefox Address bar (or Location bar) is not visible suddenly and browser looks some what similar to the image shown here. Though Navigation bar is visible; there is no space to enter a URL? Sometimes users face this issue though it is not that common. This article shows how to resolve the issue; considering the user is not an expert in configuring Firefox.

Steps:

1. Right click on area marked as "1".
2. Select Customize... (marked as "2").
3. Select the "Location" item from the pop up "Customize Toolbar" dialog box.
4. Drag and drop "Location" item to the area marked as "3".
5. Firefox itself will place the location bar correctly as earlier.

If you wish to restore all defaults items on the Firefox browser, use the "Restore Default Set" button in "Customize Toolbar" dialog box.

Related: Google redirect to incorrect country domain: Fix on Firefox

Thunderbird 3.1.5 Release with Critical security fixes

Mozilla Thunderbird 3.1.5 version released today. This free and open source email client is one of the better standalone ones available. Since development is done by a community of developers with the help of security experts; issue identification and resolution process is so efficient. Thunderbird 3.1.5 can be downloaded from here for any platform (Windows, Mac OS and Linux) in around fifty languages.

This release has fixes for five critical security vulnerabilities as shown below.

• Unsafe library loading Vulnerabilities
• Dangling pointer vulnerability in LookupGetterOrSetter
• Use-after-free error in nsBarProp
• Buffer overflow and memory corruption using document.write
• Miscellaneous memory safety hazards (rv:1.9.2.11/ 1.9.1.14)

An upgrade to latest 3.1.5 version is advised to avoid any security issues. All credit goes to those great people who devote their time and effort on getting another release out.

Attempted to lock an already-locked dir: Subversion issue

"Attempted to lock an already-locked dir" - svn: Working copy locked; this message is frequently faced by users of SubVersion (SVN) source repository. The message is self explanatory; simply some source files are locked and no commit or update operations allowed on those files/folders. In some occasions, Software developers in a team receive this message in a SVN operation even though none of them have locked the files or folders; causing confusion. So how would you try and resolve?

We use Subversion to create and store our projects in repositories; Subclipe (an Eclipse plugin) as the client tool to connect to repository.

We tried following solutions

1. Commit Changes - change and commit changes into repository
2. File Delete - delete the files and commit the delete into repository
3. Override & update - override the local changes and update from repository

None of the above options resolved the issue, but got the same type of error messages. Followings are the error messages shown inside Eclipse while trying the above mentioned options.

commit -m C:/workspace/MyProject/config.properties
    Attempted to lock an already-locked dir
svn: Working copy 'C:\workspace\MyProject' locked

update -r 13 C:/workspace/MyProject/src
    Attempted to lock an already-locked dir
svn: Working copy 'C:\workspace\MyProject' locked

delete --force C:/workspace/MyProject/config.properties
    Attempted to lock an already-locked dir
svn: Working copy 'C:\workspace\MyProject' locked

Use Cleanup command

Subversion supports a command named "Cleanup"; it is used to release the locks on a project.

If you have faced with the above issue while no one has locked the project files, you can run this command and resolve the issue.
You do this in Eclipse by right clicking the project; then Team->Cleanup as shown in the image.

Tomcat + Apache HTTP: Servers Connecting Guide

Apache Tomcat is a Servlet/JSP container and used to deploy dynamic Java contents like JSPs and Servlets. Tomcat has some web server capabilities, however it is not a full blown web server to serve high traffic web sites. In the meantime Apache HTTP server is a full blown web server. So in general Tomcat is configured along with Apache HTTP server to maintain a healthy web site with dynamic content. This article will cover the steps of configuring HTTP server and Tomcat connection, however this will not discuss installation details of Apache or Tomcat.

System Requirements

• Apache HTTP server installed
• download from here
• we used version 2.2.10 for this article
• Apache Tomcat installed
  • download from here
  • we used version 5.5 here

Short Names
Followings are the short names used to denote folders used in this article.

• %APACHE_HTTP_HOME%
• denotes Apache HTTP Server installation directory. In our testing machine, it is "D:\ASF\Apache"
• %CATALINA_HOME%
• Tomcat installation directory; for example: "D:\ASF\Tomcat"

Connection Configurations

The connection between HTTP server and Tomcat will be done using Apache Tomcat Connector module named mod_jk which is configured inside Apache HTTP server. For that first download the correct version of connector from here.

For version 2.2.10 of Apache HTTP; correct connector version is 2.2.4 (available here). Make sure to download the correct version, as incorrect version may result in errors.

Mod_jk configuration

Now the downloaded mod_jk module must be configured in Apache HTTP server. First rename the above downloaded file say mod_jk-1.2.26-httpd-2.2.4.so to "mod_jk.so". In Apache server, module files are stored under %APACHE_HTTP_HOME%\modules folder. Now copy the mod_jk.so file into this folder.

Then open the HTTP server configuration file named httpd.conf. It's located in %APACHE_HTTP_HOME%\conf folder. This file has a number of lines used to load Modules starting with "LoadModule ". Add the following line below these lines.

LoadModule jk_module modules/mod_jk.so

Now the downloaded mod_jk module is added into Apache server.

Tomcat Server Information

We need a new properties file to store details about the Tomcat server. Create a new file named workers.properties inside %APACHE_HTTP_HOME%\conf folder with the following content.

worker.list=localTomcat
worker.localTomcat.host=localhost
worker.localTomcat.port=8009
worker.localTomcat.type=ajp13

Pay attention to the above port 8009; this is the port defined inside %CATALINA_HOME%\conf\server.xml file as follows.

<!-- Define an AJP 1.3 Connector on port 8009 -->
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

If the port in AJP 1.3 connector section of Tomcat is different than 8009, change the above workers.properties file to match that.

Now we need to configure the workers.properties file in %APACHE_HTTP_HOME%\conf\httpd.conf file. For that add the following lines after the line that we added into httpd.conf in a previous step.

JkWorkersFile conf/workers.properties
JkShmFile     logs/mod_jk.shm
JkLogFile     logs/mod_jk.log

Now everything is setup. However still we have not yet defined the important part; which user requests to be forwarded to Tomcat server from Apache server.

URL Patterns

Following is the format of those configurations.

JkMount  <URL_PATTERN>  <WORKER>

• <URL_PATTERN> - the url pattern that you need to forward to Tomcat
• <WORKER> - the worker name defined in workers.properties file.

We can set up multiple url patterns as follows.

JkMount  /myProject/* localTomcat
JkMount  /*.jsp localTomcat
JkMount  /*.do localTomcat

First one will send all requests for a web application named "myProject" to Tomcat while the second will send all requests ending with ".jsp". The third line configures for all requests ending with ".do" (many use .do extension with Struts actions).

Add required configuration lines as above into httpd.conf (just after the lines we added in above steps).

Setup Completed

Now try the URLs of your application as follows (using Apache port number, rather than Tomcat port number). We assumed Apache HTTP server is running on port 80. Following as some sample urls for the above configurations.

http://localhost/myProject/
http://localhost/testApp/main/admin.jsp
http://localhost/strutsApp/login.do

Now Apache will direct all these request to Tomcat (running on a different port) and serve the client smoothly.

Related Article: How to change Tomcat port

Related Article

• How to change Tomcat port
• [Tomcat] validateJarFile(servlet-api.jar) - jar not loaded. Offending class: javax/servlet/Servlet.class
• Tomcat + Apache HTTP: Servers Connecting Guide

Google redirect to incorrect country domain: Fix on Firefox

Google servers identify the country of the googler and redirect to the relevant country domain. They may be using the IP of the request to locate the country before the redirect. However there are situations many googler getting redirected to incorrect country domains. For example, even though our requests are generating from Sri Lanka, most of the time we are redirected to another country (Taiwan) domain. Some misconfigurations at the routers or at the ISP may cause this issue, which makes it harder for a general browser user to get that resolved. This automatic redirect mechanism does not depend on the browser used.

Following is a quick fix to this issue. However this will only work on Firefox browser, sorry friends if you are on another browser.

Install Redirector extension

Redirector is a small extension available for Firefox, and it supports most of the versions ranging from 2.0 to 3.0.*. (we are using latest Firefox; 3.0.3). You can freely install it from here.
If you are a newbie to Firefox extensions; just click the "Add to Firefox" button in the web page and click "Install now" in the pop up box. You must restart Firefox, to complete this installation.

Now you will see a small icon in status bar (bottom right corner) as shown here. This is the redirector extension we installed above. You can enable/disable this extension just by clicking on this icon.

Configure a redirect

Right clicking on that Redirect icon will display a settings panel. Click "Add.." button to add a new redirect.

Now we have to fill 3 options in this new redirect box.

1). Include Pattern: Here you must try the incorrect Google country domain url. As our incorrect country domain is Taiwan, we set the following as "Include Pattern".
http://www.google.com.tw/*

2). Redirect to: This is the place where you specify the correct country domain url. As we live in Sri Lanka, following is the redirect url for us.
http://www.google.lk/$1

3). Pattern Type: Set this to "Wildcard".

It's done, quite simple. Now the Redirect settings box will look somewhat similar to the above image.

Now try and load Google home page, and it will display the country domain home page you set in the redirect settings.

Sun suspends NetBeans IDE DVD Starter Kit distribution program

Sun has suspended their NetBeans IDE DVD Starter Kit distribution program indefinitely. Yes, you read it correctly; they have done it. So many developers used to get most of Sun (free) products through the distribution program. Students with less bandwidth (in some colleges & universities); specially users without Internet access to home computers are fond of this service as NetBeans DVDs are freely delivered to their hands at no cost.

According to NetBeans.org;

"Since August 30th, 2005, NetBeans.org has shipped more than 225,000 CDs & DVDs to developers around the world through this initiative! During this period, NetBeans has experienced explosive growth as a download, media kit, and a community. To stay ahead of this encouraging trend we are looking into ways to effectively satisfy increasing demand for NetBeans software worldwide."

For sure this service played a huge role in helping so many Java developers. Also the program is a good marketing option for NetBeans since Eclipse (the best free Java IDE) provides no such services, rather than allowing free download. Sun also has decided to follow the same; stick only for free downloads. However the Starter Kit is available for download as an ISO image. In near future may offer downloads via mirrors and bit torrent; but not sure how near that future is. Anyway we are grateful to service Sun provided us.

[Eclipse] Access restriction: Class is not accessible due to restriction on required library

"Access restriction: Class is not accessible due to restriction on required library"; error message may be shown while developing Java projects in Eclipse IDE. Error message is self-explanatory, some classes can not be loaded into the project since restriction rules are being imposed on those classes.

How to solve

This error message can be removed by changing a setting inside Eclipse IDE. Open up the dialog box shown below, using any of the following paths.

• Windows -> Preferences -> Java -> Compiler -> Errors/Warnings
• (Project) Properties -> Java Compiler -> Errors/Warnings

Locate the "Forbidden reference (access rules)" option under "Deprecated and restricted API" section in the dialog box. This option decides how to handle access rules defined inside Eclipse. By default it is set to "Error" which causes Eclipse to complain about references to any restricted classes. Choosing any other option (Warning or Ignore) will remove these error messages.

"Warning" or "Ignore" options will only hide the potential issue in the project, by allowing the project to use any classes ignoring predefined access rules. To completely resolve this issue, analyze the project and located the use of restricted classes and take necessary actions (either remove those references or access rules).

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• Axis Web services Problem: No compiler found in your classpath! (you may need to add 'tools.jar')
• [Eclipse] org.osgi.framework.BundleException: Could not find bundle: org.eclipse.equinox.console

Chrome or Firefox - which browser to choose?

Chrome is the newest baby in browser family or the next competitor in browser war. What ever it is, Google released their browser named Chrome. But Mozilla Firefox is the most popular browser in the world right now and Google was the major supporter for Firefox. Even while supporting it, they have built their own browser free and open source. Here we are looking at the two browsers and trying to compare them to decide whether to switch to the new one or not leaving our old but fascinating friend Firefox?

Interesting features

1. One Process per each tab
Tab is not another thread running inside the browser process; there is a separate process per tab. Even if one tab crashes, the rest of the tabs will be running as nothing happened; which was not available in Firefox. This is one of the most interesting features.

2. New tab is filled with useful links
For a new tab in Firefox, you can load a predefined page, a blank page or a predefined set of page links (using an extension). But you would be much happier to see a set of links that you dealt with in recent past; Chrome comes exactly with that. The new tab will show a set of links;

• Most visited pages
• Recently closed
• Recently Bookmarked

I do not think the last one will be much useful, but the other two will be pretty handy.

3. Rich Location bar
Location bar in Chrome is a combination of location bar & search bar. You can directly type a url or a search keyword, also it comes with suggestions.
Using separate location bar per each tab is also an interesting move, each tab looks like individual browser instances; while in firefox you have single location bar shared by all tabs.

4. Speed
Stephen Shankland at CNet has posted an article on speed, and it tells most of the details. However Brendan at MozillaZine has published another set of testing statistics. So we'll have to check some statistics done by an independent party to get a clear view. Anyway Chrome is starting up so fast compared to any other browser.

Some complains

Since Chrome is still in beta, this may be a good time to suggest some features or improvements. Following are some complains that we have.

1. No warning in closing
When multiple tabs are opened Firefox is used to show a warning in closing the browser, but Chrome does not and closes immediately. Since people can accidentally close the browser better to add it soon.

2. Displaying different fonts
Some of the fonts are not displayed smoothly as Firefox used to do. Above image shows how the same content is displayed in two of these browsers.

3. No XML viewer
May be it is not a must to have a XML viewer in a browser, but we are used to it. Firefox and IE both have good XML viewers, but Chrome lacks it. Similar to this Opera and Safari also do not have this feature. Many people happened to work with XML files every day and having an XML viewer in the browser is an added advantage.

4. Security issues
Chrome has exposed to a set of known security issues by using an older version of WebKit, which had already been fixed. Anyway we expect Google to fix it soon.

Main Concern

Above all of these our main concern is the lack of support for extension development. We are used to live with some great extensions with Firefox, which we are not experiencing with Chrome. Since it is still in beta version, we should wait for extension support. However no API is released for extension development, users will have to wait longer than expected to see some useful extensions. There are so many extensions that makes our lives easier and better. Few of them are;

• NoScrip
• Adblock
• Gmail Manager

What are the other reasons that you are not switching to Chrome straightaway?

QuickTime security issue fixed with Firefox 2.0.0.7 new security release

Firefox 2.0.0.7 has released a new security release again. As addicted users of FF, we are really happy how Firefox progresses. When ever some issues are fixed, they provide us with a new release. Also user does not need to think twice in installing the new release as it does not add more issues to your existing installation. When Internet Explorer (IE) 7 came out users had issues; also still we have so many issues with IE7, but not with Firefox.

With this release they fixed the bug related to QuickTime; "Code execution via QuickTime Media-link files".

QuickTime Media-Link files contain a qtnext attribute that could be used on Windows systems to launch the default browser with arbitrary command-line options. When the default browser is Firefox 2.0.0.6 or earlier use of the -chrome option allowed a remote attacker to run script commands with the full privileges of the user. This could be used to install malware, steal local data, or otherwise corrupt the victim's computer. Read more

We really appreciate quick response to security issues like that.

svnadmin create a new empty project repository in subversion (svn) in Linux

If you have installed subversion (used for version control) and looking for creating a repository inside that, you are at the right place. Command to create new project repositories inside subversion is svnadmin create.

# svnadmin create repoPath
- this will create an empty repository.
- repoPath has to be a path to a folder, if that folder does not exists; new folder will be created.

Consider following examples.

# svnadmin create /usr/local/svn/clients/MyProject
or
# svnadmin create .

First command will create a repository inside "/usr/local/svn/clients/MyProject" while the second command creates a repository in your current directory.

After creating the repository, you must alter access controls. For that open conf/svnserver.conf found inside newly created repository folder.
Common values to alter are;
anon-access
- access control for non authenticated users
- better to set it to none (anon-access = none)
auth-access
- access control for authenticated users
- will need set it to "read" or "write" (auth-access = read)

Yahoo! Photos closing on different dates for different users

Today I got a mail from Yahoo informing that Yahoo Photo is shutting down. But why? As you may guess they are going to stick only to Flickr, which is one of the best solutions if someone wishes to share photos. It will be closed on 2007-10-18 for some of us while the date differs from one user to another. But anyway make sure you transfer all your photos in Yahoo Photo is moved to Flickr or download them to some other place as you will loose them for ever. Only 41 days left for me.