Tag Archives: maven

Apache Wicket [In Action]: A Review and How It Relates to the Java World

Posted by on 30 April 2013 No comments

Java is a great tool for creating software. It is well designed, modular, has a wide array of platforms that it can run on, performs well, it’s very extendable, and it has a large community with lots of support. However, it’s support for websites and related services is severely lacking. It’s bad enough that frameworks that extend the existing infrastructure have massive pitfalls that you later discover.

For the most part Apache Wicket solves many of the web related issues that J2EE (JSP) has. If you are to follow the prescribed way of doing things, it can actually be quite pleasant. However, there are a few thorny patches with Wicket. I will get to those later.

Wicket In Action like a marriage. During the honeymoon, everything is great. Everyone is happy, and then later discontent grows and things go up and down. However, unlike a marriage, you don’t really get an ending. This is a rather good way to end things, but some of the lesser parts of the book were rather disappointing. One of the big selling points of Wicket is that it is a framework that assumes that the developer has already prototyped the pages in HTML prior to starting with Wicket [The pages are adapted into Wicket-ized and previewable pages]. This upside was enough to ignore the placement of the HTML files, in the class path rather than the web resources section.

I jumped into this book with lots of enthusiasm after reading the introduction. I even bore through some of the non-stated setup issues in the book. The book starts off by creating a project, from scratch, however I went the Maven route (which I discovered is the better way to go). The book mentions maven, but it doesn’t mention how to build your application or to generate a project. I believe that I went the correct way because Maven helped to setup all of the application servers and the folder structures. The book started by having the user to jump in, examine a few code segments, and then to start on a sample (full featured) e-commerces application. The store was oddly pleasant; the goal was to sell cheeses online. The application started from a few sample view pages, it went on to creating a reusable shopping cart, and finally on to a membership mechanism. This is a very straightforward and to-the point way of starting a new framework. It’s already addressing the needs of the majority of its audience.

Another nice thing to point out about the introduction is that it did not try to cover all of the material at once. It would frequently describe what you were doing, but would mention the chapter where the concepts were explained in depth later on. Something that pleased me was that the code listings did not include a listing number. They were place in the correct location of the text. After you’re done with the sample application, you should be quite proud of yourself. This is similar to your first website.

However, the book got a little disappointing when describing the more detailed interworkings of Wicket: sessions, bookmarkable pages, and layering/rendering. The book improves when it gets to the Ajax functionality and a brief mention of dependency injection and Wicket. The book gets a little rough in the Spring through Hibernate sections and then better in the testing section. The book ends in a rather low note on SEO, production configuration, and JMX. If I had known more about JMX, I would have probably had a better opinion of the ending.

Overall I am not sure if I can say that the less than stellar sections of the book were entirely the authors’ or the book’s fault. It quite possibly may be the technology’s fault.  I would strongly recommend the book if you are new to Wicket.

Lastly, here are some direct tips that I had to discover on my own that helped out a lot:

 

Two Issues I have With IntelliJ: Inconsistent building, and GUIs

Posted by on 13 February 2013 3 comments

During the massive end-of-days sale, I bought a copy of IntelliJ. I have been primarily a NetBeans developer, but I have used IntelliJ at a previous job. So two of the things that irritated me have been: the inconsistent build support and IntelliJ’s handling of Java GUIs.

IntelliJ has its own internal build system. However, it also has support for Maven. When you have a Maven project, it adds in dependencies to the Maven file, but continues to build with its internal build manager. If you need to add a dependency, IntelliJ will automatically add the dependency in the POM file, but you have to manually add it in its own build manager. Given this inconsistency, it is possible to have two different build configurations within the same project.

Additionally, converting a project from a Netbeans based project with a GUI doesn’t work in IntelliJ. IntelliJ will not interpret the Swing code generated by Netbeans. This means that for anything GUI related, I will have to use Netbeans.

What would be nice?

Support a non-proprietary build system. NetBeans defaults to ANT, and can support Maven natively. If this is not an option, then write an adapter for Maven/ANT/Gradle.

GUI: Reuse the Mattese code. Make Mattise a plugin and write an adaptor for IntelliJ.

Progress on Tech Resolutions of 2013

Posted by on 6 February 2013 Comments Off

Earlier this year I made a few resolutions for this year.

So far I have completed the following:

  1. Finished and reviewed “Groovy In Action”
  2. Refresh on networking

Despite this not being much, I have learned many new things about disk storage, and Maven. Also, I’ve created a new GitHub repository for a ogg2mp3 script that I created.

Things left to learn/do:

  1. Finally get around to learning GridGain.   [I would love to see a well published book, or at least a Kindle eBook to get some headway on this] HazelCast would also be interesting, but GridGain has more of what I’m looking for.
  2. Finally understand how network routing works.
  3. Get more experience with DNS, and DNS tools
  4. Master NMap [not just learn the basic uses of it, but to really excel with the tool] This would be similar to the reading up on SSH I did last year.
  5. Get up to conversational level German. [Living outside of German speaking nations makes this incredibly difficult]
  6. Finally develop some strong time management habits.
  7. Learn how to use Python [to the point where you can do some cool stuff with it]
  8. Learn R [rather than haphazardly hack]
  9. Meet/talk with some of the gurus of airfare scheduling/decoding, and the famous Tom Stuker.
  10. Learn how to use GraphViz [This is one of the odd ones here, but it's interesting]
  11. Get better with Erlang and to find/make real world uses.
  12. Learn/Create a GUI in Apache Pivot
  13. Create a web interface with either Stripes and/or Wicket.

 

In Support Of Maven

Posted by on 25 January 2013 1 comment

In the last few days there has been an article completely bashing Maven on hacker news. I found this a little aggravating. Much of the article spent time complaining about how the files are structured, and how much effort it takes to maintain a Maven file. Also, the article complained about the plug-in structure.

To some extent I can agree with the original author. The plug-in system makes Maven a little difficult to learn and get completely right. On the other hand, the plug-in system makes it easy to deliver a single meta-build system that can easily adapt to what you need it to do. Building a Java web app? It has a plug-in to build and package it for you.

My main beef with the article is that it completely ignores why we got Maven in the first place. It builds, packages, and manages your dependencies better than ANT does. Before, you had to manually acquire, and grab your dependencies. If you had ANT or make, then you had to include the declarations for the dependencies in the build file, and put the dependency in your project. This is a pain for those that are using source control, and for setting up new developer machines. However, with Maven, just declare the dependency and the scope in the build file and you’re done. If you’re using an IDE it’ll bring in the references and may be able to pull the Javadoc if it’s available. Additionally, any new upgrades to the dependencies could be added just by changing the version number. Imagine doing that without a Maven like build system. Maven can even go the extra mile and create a redistributable package [this is a little tricky, but you can do it], deploy your new package to a repository, check in your code for you, or even deploy it to a webserver. For example, if you have a web service and don’t have Tomcat7 downloaded, run it with an embedded instance with mvn tomcat7:run . You’re done, Maven grabs Tomcat7, its dependences and tries to deploy your webapp to the new instance of Tomcat7. No installation of the server required.

In closing, Maven is a build tool. Unless you’re making project structure changes you shouldn’t be messing about with the way it builds things.

Links I’ve Found Interesting in the Last Week/Technical Things I’ve found Interesting (6 January 2013)

Posted by on 7 January 2013 Comments Off
  • Getting the “Application Server Libraries not found” error with IntelliJ when you try to add a local Tomcat server? If you’re using Gentoo it’s a matter of file locations. Install the tomcat-api package, and make a symbolic link from the API within the Common and Shared Tomcat directories. Source.
  • Tomcat 7 has changed around how resources can be accessed. You can no longer use “getResourceAsStream” to get files placed in the Web-inf/Classes folder. Instead, you should attempt to get the resource through the context of the local thread. An example: Thread.currentThread().getContextClassLoader().getResourceAsStream(). This is useful for applications that use JasperReports [location of the JRXML file], and that are web applications. Source.
  •  If you are trying to stand up a web server, and don’t want to allow it to accept public connections? Set the accepted connections on tomcat to only listen on the local address. For tomcat see this. For NGinx see and set it only set listen to 127.0.0.1:[port].
  • Converting a GUI Netbeans project into a Maven based project? Most of the needed libraries will be covered by the default Maven repositories. However the swing-layout dependency is a special case. To use include the Netbeans repository reference, and include the swing-layout-1.0,4 dependency.
    Repository:

    <repositories> 
   <repository>
      <id>netbeans</id>
      <name>NetBeans</name>
      <url>http://bits.netbeans.org/maven2/</url>
   </repository>
</repositories>

    Dependency:

    <dependency>
   <groupId>org.netbeans.external</groupId>
   <artifactId>swing-layout-1.0.4</artifactId>
   <version>RELEASE691</version>
</dependency>
  • Ignoring failed tests on a maven build: Add this parameter to your mvn command: -Dmaven.test.skip=true
  • Sort directories and files with a human readable format: This is like ls –Sh, but it traverses directories.
  • If you have a set of directories to ignore, SVN propset includes an option to recursively ignore specified names/folders. A word of warning propset overwrites any svn:ignore properties.

I’m a student, what [language, framework, API, concept] should I learn?

Posted by on 24 April 2012 3 comments

Part one of a continuing series.

There are two ways to learn something. The first way is to learn from another’s advice [the easy way], and then there is the hard way [through experience and making mistakes]. When starting out in a Computer Science degree, learning the material and concepts will require a lot of effort. [the hard way] It’s not a wrong way to go about it. The hard route helps to reinforce the material. However, not everything in your journey to become a software developer has to be difficult.

One of the most frustrating things for a student, when in a Computer Science program, is producing a deliverable to submit. Many students, outside of the introductory course, quickly find out that a few quick hacks won’t get the highest grade available. Many professors require documentation, specific file layouts, compliable code, funky submission instructions, build instructions, shout-outs in the comments (1), or even coding conventions. These extra/non-technical requirements add to more complexity and make assignments more difficult. However, they do have merit and “build” the student’s technical character. In academia, there are very few courses in the US that will teach the tools of the trade, this is something that the student is left to learn on his or her own.

So what does this have to do with answering the question: What should I [as a current Computer Science student] learn? Build systems. Learning how to consume a web service to Facebook or writing the next twitter client is great, however learning how to use a build system will make your professor’s, and your life much easier. A build system is an external tool [usually separated from an IDE] that defines the instructions on how to build an application. In addition, it makes your life easier when questioning if your attempt was worthy enough to submit. Did the build system pass and produce a deliverable? If you have all of the rules and unit tests configured to run, the answer is easy… Yes! Once you are confident that the assignment was completed to satisfaction, you can go party err study ‘social algorithms.’

So let’s imagine that you have the following requirements from a professor:

  • Build a chat system [One client, and one server]
  • Include unit tests for every method used
  • Include Java Doc
  • Email to: professor@university.com
  • FTP The resulting zip file to: ftp server.
  • Create a readme at the base, and include your name and the word “Screaming Monkeys” within the readme file.
  • Include instructions on how to build your software
  • Use the following file format:
    • /
    • Readme
    • BuildDoc
    • Doc/
    • Source/Client/*….
    • Source/Server/*…
    • Binary/*…

Building a working chat client and server solution may be difficult for someone that has just learned about sockets and lacks experience. The non-technical requirements could become overwhelming. However the assignment never required all of the non-technical instructions to be performed manually. I have NEVER heard of a professor that will take points off for using these tools. If anything, using a build tool will improve your grade. It allows for you to plan for these requirements ahead of time, and let software handle the rest for you.

“But hey! That looks like a lot of work to do a few simple steps!” You’re right; all of those steps can be performed manually and probably quicker. However, if you screw up part of your final deliverable [code doesn’t compile, you forgot a unit test, or the code conventions weren’t followed], you’ll have to perform all of those menial tasks all over again. With all of those tasks, Ant can perform those automatically by just typing in “ant.” You can configure ant to build the software, run all of the unit tests [and stop the build if one fails], configure the output of the java doc, run utilities [to confirm that your name is there, and the “special word”], perform all of the file manipulation and deliverable locations, and even submit the result [ftp, email, source control]. If there is an ant task for the action, you can use ant to do it.  Another benefit is that it can even run the source code through a “coding convention” checker. Have a professor that requires you to use the K&R coding convention? No problem, just add a check or reformator in the build environment. Problem solved.

In summary, assignments in computer science are difficult with the shear amount of demands. Reduce the potential for mistakes by automating the tedious tasks. Learn a build system early in your education. It will help ensure consistency in your code, get rid of annoying non-technical requirements, and make your work a lot simpler.

Need another reason? Do it for getting a job after you get out of school. There are very few students that have even used a build system prior to entering the work world. Most students entering the work world have to learn at least one build system as soon as they start their first job. The software industry thrives on build systems. If they aren’t working, the developers are unable to progress. Hey, worst case scenario: Let’s assume that you’re not a very good CS student, and you barely pass with your CS degree. If you know a build system extremely well, you can still proceed with a career of being a “Build Systems engineer.” Those guys can still make quite a lot of money. [Indeed claims that a build engineer starts at $50k and has a sizable amount of jobs that will earn $130k+ a year]

Some of the build systems that are currently in use:

  • Ant [Good for nearly every language out there]
  • MSBuild [Good for the MS supported language (VC++, VB?, anything .NET)]
  • Maven
  • Gradle
  • Make [Good for C++, and bash]
  • Apache Ivy

(1)    In my prior work as a teaching assistant I am guilty for supporting the shout-outs rule. The requirement was for the student to include his or her name in the top of the file. This was mentioned on the grading rubric (included in the assignment writeup/specs).  It’s a simple request to complete, and it makes the grader/professor’s life a lot easier. It’s akin to asking elementary school children to write their name on top of the assignment. A lot of new students don’t add their name to their code.

Lost the Passion for Software Development?

Posted by on 10 April 2012 1 comment

This is a list of potential tips to help a fellow Software Engineer recover passion in his or her work:

  1. Learn A New Language: Stuck with working solely in Java and C++ languages? Learn Erlang, or Lisp. Try out Scheme, Perl, Bash, Haskell, or D.
  2. Learn a New Framework: Some of the frameworks to learn: xUnit, Testing frameworks [other than JUnit], Spring.net, Apache Tapestry, XMPP, Esper (Complex Event Processing), OpenGL, JasperReports, OpenCV, Win32, OSGi, or even Hessian binary web services.
  3. Revive old projects by refactoring the code to use a new framework. Review code in open source projects.
  4. Attempt to become an expert in an open source project. You might become an authority on the subject, and write a book.
  5. Meet new developers. To do this, branch outside of your company and go to user groups related to the language. JUG for Java groups, LUG for Linux user groups, NUG for .NET user groups etc.
  6. Read and listen to lectures on InfoQ.
  7. Take a “Thirty Day Challenge” by coming up with a complex application and writing it in a completely unfamiliar framework or language. Something that would be rather unique, write a web application completely in Prolog or Erlang. I haven’t heard of anyone that has done that yet, but it would be rather interesting.
  8.  Annoyed with an application, language or framework? Fix it. If it’s open source, then write a fix for it and publically submit a patch. If it’s due to a closed source application, then rewrite the main interface [if it connects to a backend service], or rewrite the application completely.
  9. Have a business idea? The book “The Lean Startup” suggests that startup-interested developers should create a stripped down demo, to gauge market interest.
  10. Add new “favorite tags” to your StackOverflow account. Look for questions that contain lots of votes. Look for questions that have not been answered in a long time, research a solution and answer the question.
  11. Find ways to make your current job/task easier. If you are spending a lot of time writing the same type of unit tests over and over again, find a way to automate this, or write your own domain specific framework. Even better, write a Domain Specific Language for the current development project.
  12. Use coverage tools to find new places to test code that is currently untested.
  13. Read research papers. This is typically a very dull task, but there are some quality papers available. It takes some effort to find those papers, but the ones that are well written are worth ones effort.
  14. Hack: [I'm not responsible for unethical/illegal actions, I would suggest doing these things only for personal interest] Setup a VM to learn how to exploit system services, learn how to perform a privilege escalation, learn how to write a buffer overflow and run shell code, learn how an intrusion detection system works and attempt to exploit them, and attempt to crack legally obtained software.  [I advise that the reader do these things ethically (don't share a software crack). The reader is responsible for his or her own actions. ]
  15. “Hack Hardware”- Write an application that interfaces with an Ardinio device. Root an Android or Apple phone.  You could also go the route that Linus Torvalds went, take data from existing devices and write an application that interprets the data. His project is SubSurface, its designed to take the data from a dive-computer, and to transform it into something the user can add notes to, and visually interpret the data. Write software for an embedded processor (FPGA, Basic/Java stamp).
  16. Learn how to make your own operating system. Take a Gentoo distribution, and reconfigure everything. Try out a real time Linux distribution.
  17. Look for project suggestions on Stackoverflow. There are quite a few questions from students asking about project ideas.  One popular suggestion is to write a plugin for a popular game. From my understanding, one can write a plugin for Civilization 4 by using Python.
  18. Find ways to make your job more fun, or easier. Identify tasks that are uninteresting or tedious and find a way to automate them. Learn how to configure and/or extend a build tool. Learn Ant, Maven, or Gradle.
  19. Take a vacation: Over-working one’s self is not an achievement, no one is impressed.

Lastly, (This really isn’t considered to be a tip) to help connect with others who have a similar interest to what you’re doing, write about your attempts, successes, or failures in a blog. Even if you decide that your current job is not fulfilling, then these are things that you can mention on your resume or future employers can see on your blog.

You’re a developer, as a developer you have the unique ability to create things. There is very little holding you back from developing something you want.

Have I missed some important tips? Have these tips help you? Are there any languages or frameworks that one should study? If so, leave them in the comments box.

Fixing Classpath Issues with JasperReports, J2EE, and Maven

Posted by on 30 September 2011 Comments Off

If you are having issues with bundling JasperReports, a J2EE server, and Maven, you are not alone. There are many bumps in the road for getting JasperReports integrated with Tomcat/J2EE Container and building with Maven. Hopefully, this blog entry will make things slightly easier.

Firstly, there is the confusion of where the JasperReports dependency lies in the maven2 repository. There is a very suggestive entry for: {groupid: jasperreports, artifactid: jasperreports} however, that entry only hosts versions 0.5.0 to 3.5.3. The entry: {groupid: net.sf.jasperreports, artifactid: jasperreports} contains the versions 3.6 to the latest version. In addition, the last entry contains an artifactid of jasperreports-fonts, handy if special reporting fonts are requested from your reports.

Secondly, if you are getting ClassNotFoundException or NoClassDefFoundError for the class: net/sf/jasperreports/engine/JRException your issue with still with the POM configuration for JasperReports. The ClassNotFoundException is a runtime error, so despite a successful build, you will still see this. Despite the  jasperreports-x.x.x.jar file being in your web-inf folder, you may still see this error.

You must modify the scope of the component in the pom.xml. Change the scope from compile [which is needed to build], to “provided.” (http://maven.apache.org/pom.html#Dependencies) Provided not only uses the dependency to build, but update’s the container’s classpath to use this as a runtime dependency.

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