Welcome!

Open Source Cloud Authors: Liz McMillan, Vaibhaw Pandey, Stackify Blog, Rostyslav Demush, Pat Romanski

Related Topics: Eclipse, Java IoT, Open Source Cloud

Eclipse: Article

How to Bring Eclipse 3.1, J2SE 5.0, and Tomcat 5.0 Together

How to create a Web project that has Java classes located in different packages and how we use ANT

Eclipse is the most popular Open Source IDE on the Java market and the latest 3.1 release supports all the new language elements of J2SE 5.0.

In this article I'll show you see how to create a Web project that has Java classes located in different packages and how to use ANT to build this project and JUnit to test it. I assume that you have J2SE 5.0 installed and are familiar with Ant and JUnit.

Building Java 5.0 Applications with Eclipse
We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's "Reload" button). If the counter goes over five, the counter gets cleared.

Installing Tomcat
I've used Tomcat 5.0, which is available at http://jakarta.apache.org/tomcat/. Installation is a breeze, and it's smart enough to find your installation of J2SE 5.0. It also lets you test Java servlets easily on your own machine. Other that making you restart the server every time a new servlet is deployed, Tomcat is a great server for what we're doing and many other tasks.

Creating a New Project in Eclipse
To create our servlet, start by creating a new Java project by selecting the menus File, New, and Other. Then specify the name of the project, say, MyJavaProject, (make sure that J2SE 5.0 is selected as the default JRE), and click Finish. Actually, Eclipse lets you select a different version of the Java runtime at any time using the menus Windows, Preferences, Java > Installed JRE's. You can also set the compiler compliance level on the project level by selecting Java Compiler under the project's properties.

Since the standard J2SE 5.0 SDK doesn't support servlets, let's add the servlet.jar that comes with Tomcat. It's in its directory common\lib\servlet-api.jar. To add this external jar to an Eclipse project, right-click on MyJavaProject, select properties, Java Build Path, and under the Libraries tab add this external jar. Now our servlets will compile.

Eclipse by itself doesn't support debugging with Tomcat unless you add some custom Web development plug-ins to it, such as Web Tools Project (WTP). It's possible to debug Tomcat applications using Eclipse remote debugging capabilities. For more information see the Java Developer's Journal at http://java.sys-con.com/read/44918.htm.

Some of the New J2SE 5.0 Features
Let's create several supporting classes that will be used by our servlet and demonstrate some of the J2SE 5.0 capabilities. It's always a good idea to keep classes in separate packages based on functionality or some other criteria. Let's call the package "support." Just right-click on the project name, select "New Package," and enter the package name.

Autoboxing
Create a new class called Boxer that will support Java 5.0 enhanced boxing and unboxing operations. Right-click on the Java project, and select a New Class (un-check creation of the main method). Enter the source code of the class as shown in Listing 1 at the end of the article.

Just press Ctrl-S and the class is saved and compiled. As you can see, it has three methods for boxing, unboxing, and simplified adding to a collection.

Generics
Now create another class called Generic that shows how to eliminate the need for casting when retrieving elements from a collection by introducing generic collection types. You can specify the type of collection elements during its creation (see Listing 2). Generic types let objects of the same class operate safely on objects of different types. For example, they provide compile-time assurances that a List<String> always contains Strings and a List<Integer> always contains Integers.

Eclipse can handle both generic and non-generic types:

  • Generic types can be safely renamed.
  • Type variables can be safely renamed.
  • Generic methods can be safely extracted from or inlined into generic code.
  • Code assist can automatically insert appropriate type parameters in parameterized types.
In addition, a new refactoring option has been added. "Infer Generic Type Arguments" can infer type parameters for every type reference in a class, a package, or an entire project.

Enhanced For Loop
The next useful feature of J2SE 5.0 provides support for the enhanced "for" loop. This spares us from creating an iterator, navigating it, and retrieving elements from it. Create this class in Eclipse in the same package support (see Listing 3).

Java printf Function
Now, C-lovers, you can use the printf function in Java so create one more class as in Listing 4.

Methods with Variable Number of Arguments (varargs)
Java 5.0 lets you create methods with a variable number of arguments as in Listing 5. This method's signature is pretty similar to the public static String[] format(String str, Object[] args), however, it's more elegant to invoke since multiple arguments can be just passed on the command line rather than having to construct a whole new array.

Don't forget to create this class in the package support.

Static Imports
Allows importing static constants and methods, saves on extra mentioning of static classes (see Listing 6).

Creating a Servlet
Now that we've created all the supporting classes, let's create a servlet. First, we create a new package called servlet in our project.

Then, we can just create a SampleServlet class by selecting HttpServlet as a superclass in the Eclipse class creation window.

Servlets can handle all the HTTP protocol invocation types. GET and POST are the most common ones, through. Servlet code is in Listing 7.

More Stories By Boris Minkin

Boris Minkin is a Senior Technical Architect of a major financial corporation. He has more than 15 years of experience working in various areas of information technology and financial services. Boris is currently pursuing his Masters degree at Stevens Institute of Technology, New Jersey. His professional interests are in the Internet technology, service-oriented architecture, enterprise application architecture, multi-platform distributed applications, and relational database design. You can contact Boris at [email protected]

Comments (13) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
sumeet jaju 07/28/06 07:40:26 AM EDT

Thanks for you

SYS-CON Belgium News Desk 01/07/06 02:16:35 PM EST

We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's 'Reload' button). If the counter goes over five, the counter gets cleared.

SYS-CON Australia News Desk 01/06/06 12:59:13 PM EST

We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's 'Reload' button). If the counter goes over five, the counter gets cleared.

Lester D'Souza 01/06/06 12:24:47 PM EST

A great article. I had to struggle to get it working due to some errors and typos. I wish I could upload my entire Eclipse project as part of the feedback. The nice thing about this set up was that I could modify my Servlet, then using the create-war, undeploy and deploy my changes on the tomcat server with the click of a button. Tomcat would detect my changes, and when I refreshed the browser, I could see my changes. This is an ideal setup for any web based development. Also I would like to mention that this is my first experience with Eclipse, Tomcat and Ant. I would like to rewrite this article and leave out the J2SE 5.0 stuff, since it does not fit in very well. Also I was able to use Junit to test the code.

Eclipse News Desk 01/05/06 08:31:49 PM EST

We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's 'Reload' button). If the counter goes over five, the counter gets cleared.

SYS-CON Australia News Desk 01/05/06 07:38:14 PM EST

We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's 'Reload' button). If the counter goes over five, the counter gets cleared.

Carrie Latimer 01/05/06 07:01:44 PM EST

I ran into the same issues Eric ran into. Help please. Thank you and take care.

Carrie Latimer 01/05/06 07:01:34 PM EST

I ran into the same issues Eric ran into. Help please. Thank you and take care.

Eric Bresie 11/16/05 09:02:26 AM EST

I was reading your article about Eclipse and Tomcat and was trying to follow on and ran into a snag or two.

One problem that I did find was that the SampleProgram has a class name in the file of TestProgram.

The other problem, and I'm not sure if this may not be an Eclipse project setup issue, environment issues, or something else, but when I try to compile the SampleProgram and reference the ForLoop's convertToString, it indicates that it cannot be resolved. I believe I have the classes included into the project correctly, so I am still a little confused.

Since this is my first encounter with Java 5's new features such as the new forloops, I am not as familiar with this and was hoping you might have some idea.

Do you have any ideas? Have you encountered a similar problem?

Thanks ahead of time.

Eric Bresie
[email protected]

Servlet Newbie 11/10/05 12:22:30 PM EST

Very good article!

...however: I cannot seem to get the servlet running. I can see that it is deployed, but if I type http://localhost:8080/myapp/SampleServlet/
it gives me a required resource not found...

Help please

Eugenio Leal 11/01/05 07:47:57 PM EST

Eclipse sucks. Websphere sucks. Netbeans Rules.

Bernie's ramblings... 10/20/05 04:46:38 AM EDT

Trackback Added: Eclipse, J2SE5 and Tomcat; I’ve always liked to read about Eclipse, and knowing more about it has often made me able to work better. There’s always just some gurus out there that seems to be able to make programming a bit more bearable. An article I came across today...

Enterprise Open Source Magazine News Desk 10/17/05 03:31:03 PM EDT

Enterprise Open Source Magazine - How to Bring Eclipse 3.1, J2SE 5.0, and Tomcat 5.0 Together
We'll build a servlet that will demo some new Java 5.0 features and do some basic tasks like creating a session to track user visits to multiple Web pages. This code can easily be extended to store a user ID in the session that will travel with her as the site is navigated. The value of the visit counter is stored in the session so multiple visits to the page will be counted (this includes the page refreshes after pressing the browser's 'Reload' button). If the counter goes over five, the counter gets cleared.

@ThingsExpo Stories
"MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, introduced two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a multip...
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
SYS-CON Events announced today that Evatronix will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Evatronix SA offers comprehensive solutions in the design and implementation of electronic systems, in CAD / CAM deployment, and also is a designer and manufacturer of advanced 3D scanners for professional applications.
Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
An increasing number of companies are creating products that combine data with analytical capabilities. Running interactive queries on Big Data requires complex architectures to store and query data effectively, typically involving data streams, an choosing efficient file format/database and multiple independent systems that are tied together through custom-engineered pipelines. In his session at @BigDataExpo at @ThingsExpo, Tomer Levi, a senior software engineer at Intel’s Advanced Analytics gr...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things’). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing? IoT is not about the devices, it’s about the data consumed and generated. The devices are tools, mechanisms, conduits. In his session at Internet of Things at Cloud Expo | DXWor...
Everything run by electricity will eventually be connected to the Internet. Get ahead of the Internet of Things revolution. In his session at @ThingsExpo, Akvelon expert and IoT industry leader Sergey Grebnov provided an educational dive into the world of managing your home, workplace and all the devices they contain with the power of machine-based AI and intelligent Bot services for a completely streamlined experience.
SYS-CON Events announced today that Synametrics Technologies will exhibit at SYS-CON's 22nd International Cloud Expo®, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Synametrics Technologies is a privately held company based in Plainsboro, New Jersey that has been providing solutions for the developer community since 1997. Based on the success of its initial product offerings such as WinSQL, Xeams, SynaMan and Syncrify, Synametrics continues to create and hone inn...