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Created by Fang on January 10, 2010 00:19:30    Last update: January 31, 2012 16:28:42
Maven is a powerful yet complex tool. When I started learning Maven, the first obstacle was, of course, its complexity. The second, was the lack of documentation that can get me off the ground quickly. This tutorial is an attempt to create a pragmatic guide that aims to get you familiar with Maven in the quickest way possible. The main theme is to get you on some hands on experience to start out and lead you through the creation of a simple Java EE project as quickly as possible. Instead of trying to give you a good read, I try to get you on the journey right away. The topics are roughly ordered by the logical sequence but you can jump around in any way...
Created by Fang on November 08, 2011 14:40:57    Last update: November 08, 2011 14:40:57
This error happened when I loaded a JSF page, using Apache MyFaces. From the stack trace it looked like the XML parser failed, but in reality the runtime was not able to load the class specified in the handler-class element - a typo in the class name! That's the price you pay for wiring together components with XML! This was the stack trace: Caused by: org.xml.sax.SAXException: Error Handlin...
Created by Fang on October 22, 2011 19:51:05    Last update: October 22, 2011 20:31:48
I built a very basic JSF application and deployed to Tomcat 7.0.22, but it failed with this error: Caused by: java.lang.ClassFormatError: Absent Code... That looks weird and I wasn't able to find a sensible explanation! So I copied the jsf-api-2.1.jar , which was downloaded from the java.net Maven repository by Maven, into a temp folder. And tested it with this simple program: public class ClassFormatErrorTest { public ... I also copied servlet-api.jar from Tomcat's lib folder to the temp folder. Sure enough it failed with the same error: C:\tmp>java -cp .;jsf-api-2.1.jar;servlet-api.jar ... But when I replaced the javax.faces.webapp.FacesServlet class with one I compiled from source, the error disappears! Conclusions: The jar file jsf-api-2.1.jar from java.net Maven repository is good for compilation only (cannot be used...
Created by freyo on July 21, 2011 12:58:59    Last update: July 21, 2011 13:02:17
From Android Developers : You can use a third party JAR in your application by adding it to your Eclipse project as follows: In the Package Explorer panel, right-click on your project and select Properties . Select Java Build Path , then the tab Libraries . Press the Add External JARs... button and select the JAR file. Alternatively, if you want to include third party JARs with your package, create a new directory for them within your project and select Add Library... instead. It is not necessary to put external JARs in the assets folder. Apparently, this is not working for me! I added a libs folder, put the external jar in libs . The project built fine, but the APK does not include the...
Created by freyo on May 17, 2011 11:13:17    Last update: May 17, 2011 11:13:17
This is an odd-ball content provider in that it doesn't provide database records, but provides a resource as a stream. It can be used to provide media files or XML resources. Start the project with: tools/android create project --package com.android... Create assets directory and add an XML file ( assets/demo.xml ): <? xml version="1.0" encoding="UTF-8"?> <people... Edit the layout ( res/layout/main.xml ): <?xml version="1.0" encoding="utf-8"?> <LinearL... Edit src/com/android/cptest/Dummy.java : package com.android.cptest; import java.io.... Add content provider ( src/com/android/cptest/XmlResource.java ): package com.android.cptest; import java.io.... Update AndroidManifest.xml : <?xml version="1.0" encoding="utf-8"?> <manifes... Add this section to the end of build.xml : <target name="-package-resources"> <ech... Build and install: ant install Screenshot: Remove the Dummy activity ( AndroidManifest.xml ): <?xml version="1.0" encoding="utf-8"?> <manifes... Create a new project for...
Created by nogeek on February 03, 2011 13:08:38    Last update: February 03, 2011 13:14:10
The log line was like this: 2011-01-19 15:16:34,842 INFO [STDOUT] (HDScanne... Note that INFO and timestamp were printed twice. Based on my configuration, I was expecting something like this: 2011-01-19 15:16:34,842 INFO [XmlWebApplicationC... i.e., the logger name should have been XmlWebApplicationContext , not STDOUT ! What was the problem? I found this error message in server.log : 2011-01-19 14:34:38,107 ERROR [STDERR] (main) lo... It turned out that org.apache.log4j.Appender was loaded by my web application class loader, whereas org.jboss.logging.appender.FileAppender was loaded by the JBoss bootstrap class loader. Removing the log4j jar from my web application archive fixed the problem (sine log4j is already available in JBoss). Why was the logger changed to STDOUT? JBoss detects that there's a problem with the log4j configuration and routes all...
Created by Dr. Xi on June 01, 2010 16:44:12    Last update: June 01, 2010 16:45:52
I installed JDK 1.6 under C:\jdk1.6.0_20 and unpacked Eclipse GALILEO in C:\local\eclipse . When I launched Eclipse with eclipse.exe , it simply displayed a splash page and shutdown. Running eclipsec.exe displayed some vague errors: C:\local\eclipse>eclipsec Error occurred during... Turning on debug: C:\local\eclipse>eclipsec -debug Start VM: -Dos... The Solution: add -vm option to eclipse.ini : -startup plugins/org.eclipse.equinox.launcher_1...
Created by Dr. Xi on March 22, 2010 01:50:49    Last update: March 22, 2010 01:50:49
The class org.apache.xerces.jaxp.SAXParserFactoryImpl extends javax.xml.parsers.SAXParserFactory , so casting the former to the latter should not be a problem. This error occurs when there are two copies of javax.xml.parsers.SAXParserFactory loaded by two different class loaders, and you are trying to cast one to the other. Normally, you'll be able to find xml-apis.jar under WEB-INF/lib of the WAR file. Deleting the jar will resolve the problem. java.lang.ClassCastException: org.apache.xerces.ja...
Created by Dr. Xi on January 30, 2009 16:57:12    Last update: January 30, 2009 17:25:36
The scriptable attribute defaults to false . However, even when you set it to true , there is a time delay between when the applet is loaded and when it becomes scriptable . The following code may fail: <html><body> <object classid="clsid:8AD9C840-04... You need to wrap the JavaScript like this: <script language="JavaScript" type="text/javascrip...
Created by Dr. Xi on August 10, 2007 19:53:32    Last update: August 10, 2007 19:53:32
As a Java developer, I often need to find out which Jar file to include on my classpath in order to fix some compilation error (undefined package, class etc). This is a little Perl script I wrote to facilitate this task. #!/bin/perl # find jar containing specified...