Nine years ago I’ve written an e-book “Programming in Java for kids, parents, and grandparents“. If was a self-published book, which I offered for downloads free of charge. A year later fellow software developers from France translated it to French. Last year, a group of developers from Eastern Europe translated it to Russian language. All these versions are available for free, and I’m really glad that non-programmers of all ages can start learning this widely-used programming language without the need to have any serious background in programming.

Today, I got a message that my book is pretty popular among Russian-speaking people. The Russian translation of my eBook is #2 with 13667 downloads from this site, and the original English version is #13 in this bestellers list.

Only Herbert Schild is ahead of me at this point. Yay, time to celebrate! But there is a bitter taste in my mouth. The reason being that this statistics was taken from the torrent site rutracker – the main site for downloading of illegal content. I’m really glad to find myself among a very respectful group of Java authors, but most likely my book is the only one in this list that’s offered without violations of the copyright.

There was this joke that “Mixed Feelings is when your mother-in-law gets into a serious car accident while driving your new Mercedes”. It seems that I can offer a new definition of what the Mixed Feelings mean…

Yesterday, I was teaching my Sunday online Java class. One of the topics was Java annotations. I was explaining that a program’s metadata is the data about your code. Any Java class contains its metadata, and you can write a program that “asks” another class, something like “What methods do you have?”. After explaining how to declare a custom annotation @MyJDBCExecutor I gave a code snippet that may use it:

@MyJDBCExecutor (sqlStatement="Select * from Employee”)
 public List getEmployees(){
      // The code to get the the data from DBMS goes here,

      // result set goes in ArrayList, which is returned to the 

      // caller of the method getEmployees()

      …   
      return myEmployeeList;
}

One student asked me a question, “How you can access the value of the sqlStatement from inside the method getEmployees()?” This was a clear signal that I didn’t do a good job of explaining what metadata is for. I started to think of an example from the real world illustrating metadata, and this is what I came up with.

When you check in your luggage at the airport, they put this sticker tape that includes the luggage ID, destination, the airline carrier and the flight number. This can be considered a metadata about your piece of luggage. It’s meant to provide some additional information about your bag and is supposed to be read and interpreted by those who are handling the luggage, not by the luggage itself.

If there is a pair of jeans inside your luggage it could care less what the sticker on the bag reads. On the same note, the code from inside the method getEmployee() is not supposed to read and interpret the data that was written on its “sticker” (a.k.a. annotation).

Software developers who create custom annotations have to create another piece of software (annotation processors) that would introspect your class, find and interpret all annotations that are present and perform the appropriate action. In the ancient pre-Java6 times, there was a special tool for that called APT. Now it’s deprecated because its functionality was incorporated inside the javac compiler itself. But this is another story. I hope my analogy with luggage stickers will help junior Java developers in understanding of the very important concept of metadata.

If you are teaching or studying Java, feel free to download the slides to my Java training at this site.

While Eclipse IDE is not the best one for JavaScript developers, it’s the most popular IDE among enterprise Java developers. If an enterprise Java developer needs to start developing in JavaScript, the first question comes to his/her mind is “Can I stay with my familiar Eclipse”.

At this point some people will start thinking, “Doesn’t he know that IntelliJ IDE or WebStorm are the best for JavaScript?” I know. I was not sitting under the rock. But you may be surprised, but having your project manager spend $50 on the WebStorm license may be mission impossible.

But let’s talk not just about any JavaScript, but about Ext JS from Sencha that includes megabytes of the source code, which will keep Eclipse busy for a while. All of a sudden, it’ll start doing its indexing spiel, which will drive you crazy.

Sencha engineers created an Eclipse plugin, with context sensitive help that doesn’t put Eclipse into this indexing mode. They solved this problem by creating a special type library file (ext.ser) supporting code assistance in Eclipse. This solution will work until some of the Ext JS API changes, after that Sencha should update the type library file.

After that, Sencha marketing people put it in a gift box titled “Sencha Compete” with a little price tag that read $900. To be fair, this box has other stuff too, but you can’t just purchase Sencha Eclipse plugin, say for $50. Spending your own $50 may not be the option in large corporations that are limiting what you can install on the company computer.

In any event, I’ll share with you how Ext JS developers of Farata Systems deal with this situation when they have to work in Eclipse IDE with Ext JS. Our developers usually need to program the server side in Java hence they need to deploy the code under one of the Java servers, e.g. Apache Tomcat. They use different setups and I’ll show you a couple of them. you’ll see how to to configure Tomcat inside the IDE and then add Ext JS to your Web applications.

Installing Eclipse for Java EE Developers

We’ll use the “Eclipse IDE for Java EE developers” version of this most popular IDE among Java developers. It’s available free of charge at Eclipse Downloads site. The installation comes down to unzipping of the downloaded archive. Then double-click on the Eclipse executable, and it’ll start.

Apache Tomcat

http://tomcat.apache.org%5BApache Tomcat is probably the most popular free and open source server used by Java developers for deploying Web applications. Besides being a Web Server, Tomcat also contains Java Servlet container.

Get the latest version of Apache Tomcat from the Download section at http://tomcat.apache.org. At the time of this writing Tomcat 7.0.39 is the latest build, so download the zip file with the Tomcat’s Binary Distributions (Core). Unzip the file in the directory of your choice.

Even though you can start Tomcat from a separate command window, the more productive way is to configure Tomcat right in the Eclipse IDE. This will allow to deploy your applications, and start/stop Tomcat without the need to leave Eclipse.

To add a server to Eclipse, open Eclipse Java EE perspective (menu Window | Open Perspective ), select the menu File | New | Other | Server |Server | Apache | Tomcat v7.0 Server, select your Tomcat installation directory and press Finish. If you don’t see Tomcat 7 in the list of Apache servers, click on “Download additional server adapters”.

You’ll see the Tomcat entry in the Eclipse Project Explorer. Go to Eclipse menu Windows | Show View and open the Servers view. Start Tomcat using the right-click menu.

TIP

By default, Eclipse IDE keeps all the required server configuration and deployment files in its own hidden directory. To see where exactly they are located in your computer, just double-click on the name of Tomcat in the Server view. The server path field contains the path. Keep in mind that while Tomcat documentation defines webapps as a default deployment directory, Eclipse uses wtpwebapps directory instead. If you prefer to deploy your Eclipse projects under your original Tomcat installation path, select the option Use Tomcat Installation.

In the next section you’ll learn how to create Dynamic Web Projects in Eclipse, where you’ll need to specify the Target Runtime for deployment of your Web applications. This newly installed and configured Tomcat server will serve as a deployment target for our sample projects.

Dynamic Web Projects and Ext JS

Eclipse for Java EE developers comes with http://www.eclipse.org/webtools/%5BWeb Tools Platform] that simplifies development of Web applications by allowing you to create so-called Dynamic Web Project, which will be specifically created for deployment under a particular Java server – Apache Tomcat in our case.

To create such a project select Eclipse menu File | New | Other | Web | Dynamic Web Project. It’ll pop up a window similar to shown below. Note that the Target Runtime is Apache Tomcat v7.0 that we’ve configured in the previous section.

Upon creation, this project will include several directories, and one of them will be called WebContent. This directory it serves as a document root of the Web server in Eclipse Dymamic Web Projects . This is the place to put your index.html and one of possible places to keep the Ext JS framework.Create a subdirectory ext under WebContent and copy there all files from the Ext JS distribution. The app directory should also go under WebContent.

Unfortunately, Eclipse IDE is infamous for slow indexing of JavaScript files, and given the fact that Ext JS has hundreds of JavaScript files, your work may be interrupted by Eclipse trying to unnecessary revalidate these files.

If you don’t have Sencha Eclipse plugin, there is a couple of solutions to this problem (we’ll use the first one).

1. Exclude from Eclipse build the following Ext JS directories: ext, build, and packages.

2. Don’t copy the Ext JS framework into your Eclipse project. Keep it in the place known for Tomcat, and configure as a loadable module.

To implement the first solution, right click on the properties of your project and select JavaScript | Include Path. Then switch to the Source tab, expand the project’s Web content and press the buttons Edit and then Add. One by one add the ext, build, and packages as exclusion patterns (add the slash at the end).

For the second solution, In this case you’ll need to add your Ext JS folder as a static Tomcat module. Double-click at the Tomcat name in the Servers view and then click on the bottom tab Modules. Then click on Add External Web Module. In the popup window find the folder where your Ext JS is (in my computer it’s inside the Library folder as in below screensot) and give it a name (e.g. /static/extjs-4.2).

Now Tomcat will know that on each start it has to load year another static Web module known as /static/extjs-4.2. If you’re interested in details of such deployment, open up the file server.xml located in your Eclipse workspace in the directory .metadata/.plugins/org.eclipse.wst.server.core/tmp0/conf.

To ensure that you did everything right, just enter in your browser the URL http://localhost:8080/static/extjs-4.2, and you should see the Ext JS Welcome screen.

In both of these solutions you’ll lose the Ext JS context sensitive help, but at least you will eliminate the long pauses caused by Eclipse internal indexing processes. Again, developing ExtJS code in Web Storm IDE or IntelliJ IDEA IDEs would spare you from all these issues. To see how to configure IntelliJ Idea with Ext JS, see this video in our Youtube Channel.

P.S. If you know of other and better ways of working with Ext JS inside Eclipse IDE, please share it with everyone by leaving a comment at this blog.