Category Archives: Programming languages

Eclipse Quick Tip: Resolving Error “The import javax.servlet cannot be resolved”

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When you start to develop web application using Java, you may think to use Eclipse as the IDE. Assume that you have seen a good tutorial about Java servlet on the internet or read the chapter of a book discussing about web development using JSP.

You are now writing the first servlet by using the wizard provided by the IDE. However, as soon the template file is loaded on the source code editor, you encounter the infamous error “The import javax.servlet cannot be resolved” just like depicted in the figure below.

Servlet import error

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Quick Tip: Configuring Eclipse to Run for the First Time

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Eclise GalileoFor Java developers, Eclipse is a convenient tool to develop software in broad range of programming languages. This tip is intended to help fellow developers who never use Eclipse before but are eager to start developing applications using Eclipse IDE.

Even though Eclipse is cross-platform, there is no guarantee that the tip provided in this post will also work for version of software and environment other than ones described below:

  • OS: Windows
  • Eclipse version: Eclipse 3.5 Galileo
  • JDK version: Java EE 6 SDK

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Comprehensive Guide to Java (JRE and JDK) Installation on Fedora Linux – Tips and Tricks

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Sun's Java JRE and JDK on FedoraIn this article, you will be exposed to the installation of Sun Java in Fedora Linux. Although Java has been installed by default in every fresh Fedora package, the Java version shipped along with the OS package is the open-source version GNU Java instead. Some applications and frameworks may require Sun Java. Due to licensing issues, however, Sun Java can not be bundled with the default Fedora Linux package and should be installed separately. Although the installation steps in this article can also be reproducible in other Linux distributions, there is no guarantee that steps advised in this article will also work for other Linux distributions.

The installation of Sun Java in a Fedora Linux box can be seamlessly easy. Yet, some people especially those with minimum technical experience on *NIX OSes may face difficulties in completing the installation. This article tries to provide a comprehensive guide for the installation. It provides whole steps to be followed along with corresponding snapshots so that one can accomplish the installation successfully. It also shares some useful tips which may help readers in understanding the environment they are working on better.

Prerequisites and constraints

This installation assumes that the following requirements and constraints have been fulfilled:
1.    Installation will be conducted through the console prompt.
2.    User conducts the installation using root account.
3.    The software yum must have been already installed in the box.
4.    The software wget is already installed in the box.
Tip: if wget is not installed yet, run command yum install wget from the console and the software will be immediately installed.
5.    Fedora version used is Fedora 8.0 or newer.
Note: in legacy Fedora, there is different path in installing the compatibility libraries. You can check jpackage site for more information.
6.    JRE and JDK version to install is 1.6 (snapshots are for JRE and JDK 1.6 update 17)
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Sizzling Upload Progress Bar in PHP with APC, Part 1: APC Installation

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After some series of “political” technical notes, I think it’s the right moment to supply some more technical posts to fellow developers. This time I will write about creating sizzling upload progress bar in PHP. In the past, there had been heated debate in PHP internal list about RFC 1867 implementation on PHP core code. If you were there, you might still remember that we had to patch the file main/rfc1867.c and some other files and then recompile PHP to get the upload progress bar hack working. Some harsh critics even mentioned that without the built-in capability of upload progress, PHP was years behind Java and Perl and lacked its capability as a web programming language.

Fortunately, since PHP 5.2 (especially after PHP 5.2.6 release), showing upload progress is not a big deal in PHP. Thanks to APC developers -mostly are also core PHP developers- who contributed to changes in APC that led to the availability of this long-waited feature. With APC we’ll be able to track the progress of file upload and provide our users better convenience when using our application.

Still, APC is not a part of core PHP shipped as a bundled package. We need to install it manually. In Windows, we can simply load the dll file to get it working. However, Linux users may need some pointers about how to install and enable this package. Hence, I will provide some guide for APC installation which was tested on veteran RHEL 4 and energetic young Fedora 10. So, let’s just go to the installation part. Continue reading →