I'm using NetBeans 8.0 and my problem is when I make (clean and build) to my java project....the jar will be build in the current path of the project and works good with no problems, But, when I make a copy of the jar to my desktop, the application jar doesn't run. why?
Except for the most trivial programs you cannot just copy a jar file containing your classes to a target machine and expect it to run, as Sun never got around to do a well-defined single-file deployment method for a desktop application (similar to what WAR files do for web applications).
You must essentially copy your code, and the library jars you depend on, and a launcher script telling the JVM which jars you have, and an icon if you want that and usually more too. The lack of a standard method means that there are many ways to do it and you need to choose the one best suitable for you.
A solution for your problem here and now is to look at https://netbeans.org/kb/articles/javase-deploy.html which discusses how to deploy Java SE applications using netbeans by creating a runnable jar with an embedded classpath. I am not very familiar with Netbeans but the steps look very sensible and will teach you the details on the process.
When you get more experienced you will want to be able to automate the process more. The first step in that direction is to learn Maven - a bit tedious in the start but it pays of in the long run.
I am experimenting with my first GWT app that uses GIN. I am essentially mimicking the exact same source code example found in their Getting Started tutorial. At the end of that tutorial, the author mentions that you need to supply the the GWT compiler with a classpath pointing to the compiled Java binaries. The example they use for doing this is done using an Ant target.
Although I will have an automated (Ant-driven) build that also emulates this build task, I want to be able to run/debug my GWT apps from inside of Eclipse without having to kick off an Ant build.
So I ask: when running my GWT app inside Eclipse (Dev Mode), how do I configure the GIN library to point to the compiled classes? Thanks in advance!
All you should need to do is add the gin.jar (and dependencies, probably just guice.jar) to your project's classpath.
It should not be required to copy these to WEB-INF/lib/, though depending on your server setup, you may require guice.jar there, but never gin.jar.
I am currently working on a small program that should comment out some code used for testing.
I want it to auto run before the compiler while compiling the release version and another program that will comment the code back in after compilation was over.
The program works the only thing I am missing is to add it to the build process.
Thanks to all helpers!
In Eclipse, right-click a project, choose Properties → Builders and click New. You can add an Ant script or a command line that Eclipse will trigger when building the project. You can also control the order of builders in the same dialog.
However, I agree with JB Nizet – there are many advantages to having Ant or Maven build your project.
Don't use Eclipse to build the release version of your app. Use Ant, Maven, or any other build tool that is much more flexible than Eclipse, doesn't need a GUI, can be scripted and used by a continuous integration server.
All of these tools should easily be used to include your pre-compilation and post-compilation tasks in the build process.
That said, you could just use a public static final boolean constant FOR_TEST, and include all your testing code in
if (TestUtil.FOR_TEST) {
}
You would then have just a single place to change in the code to have all the test code removed from the compiled version. No need for a complex Java program to do that.
Or you could let all the testing code in the released version, and activate it when testing using a system property, for example. This wouldn't even need any precompilation/postcompilation phase, and would probably have a negligible cost.
I have looked for an answer for this nearly every where that I can think of, but there doesn't seem to be any way to actually SEE what Eclipse "runs" to compile the projects (as it does need the JDK installed and visible to actually build). I ask because I imported a few jars into my project, and even though I've looked through all the javac documentation, I can't seem to figure out how to mimic it quite like Eclipse does. I really, really need to be able to compile on the command line in this case - Eclipse or any other IDE just isn't what is needed.
I started to look through the Eclipse source, and although this sounds lazy, I just became overwhelmed and figured I would ask here first, hoping someone else had the same question at one point.
Eclipse JDT does not require the JDK and does not use javac - it uses it's own compiler.
You can see the classpath by reading your project .classpath file. The various builders that are used to perform build operations (Java, or whatever the project builds) are listed in the .project file. (These are also listed in the project settings.)
It is possible to invoke Eclipse to build your project in headless mode, or write Ant scripts that can be executed both with the JDK and within Eclipse, or install Maven support for internal and external building. It is also possible to configure the project builders to rely only on external tools.
Look at these two articles.
http://www.eclipse.org/articles/Article-Builders/builders.html
http://www.eclipsepluginsite.com/builders-natures-markers.html
Look at your .classpath file and start building an ANT build.xml. You need to do this to be able to have consistent builds on a build machine anyways. It is unlikely that a build server would have eclipse installed on it anyways.
Maven is also another tool that is used for builds. In our shop we use Ant.
Have a look at ant4eclipse - this project allows for generating the appropriate ant data structures for invoking <javac> from the .classpath files and a projectSet.psf file.
By using this we can use Eclipse "natively" and bend ant to conform to Eclipse. The usual approach is the other way around.
I see reference of ant a lot but I don't get exactly what its meant to do? from what i've heard its supposed to compile your projects but can't i just do that by clicking Run->Run in eclipse?
Edit : I guess I should rephrase my question. I already know that ant is a 'build automation software', my question is, what exactly is build automation? I thought that you're supposed to test your app, and when it is running you click the 'build' button in eclipse or through command-line java, and it makes a .jar file out of it? So why do you need to 'automate' this process?
I already know that ant is a 'build automation software', my question is, what exactly is build automation? I thought that you're supposed to test your app, and when it is running you click the 'build' button in eclipse or through command-line java, and it makes a .jar file out of it? So why do you need to 'automate' this process?
Not all the Java development is done through eclipse and not all the jars may be built from the command line ( or should be built from the command line ) .
You may need additionally run test cases, unit tests, and many, many other process.
What ant does, is provide a mechanism to automate all this work ( so you don't have to do it every time ) and perhaps you may invoke this ant script each day at 6 p.m.
For instance, in some projects, a daily build is needed, the following are the task that may be automated with ant, so they can run without human intervention.
Connect to subversion server.
Download/update with the latest version
Compile the application
Run the test cases
Pack the application ( in jar, war, ear, or whatever )
Commit this build binaries to subversion.
Install the application in a remote server
Restart the server
Send an email with the summary of the job.
Of course for other projects this is overkill, but for some others is very helpful.
rogeriopvl is absolutely correct, but to answer your "can't I just do that by clicking Run->Run in Eclipse?" question: that's fine for a project that you're working on on your own, and don't need a repeatable, scriptable build in multiple environments.
If you're working on an open source project, however, or professional software which needs to be able to build on a build server etc, requiring a particular IDE to be running isn't a good idea.
Ant is used to automate a build process, but a build process is often much more than compiling. Ant has "tasks" that can be used to perform miscellaneous useful functions. You can create your own task to do just about anything by writing a java class and telling ant where to find it. You can then mix and match these tasks to create targets that will execute a set of tasks.
You can also set up a dynamic environment in which to build your application. You can set up property files to hold variables that can be used in the build process, i.e. to hold file paths, class paths, etc. This is useful for instance to differentiate between test and production builds where deployment paths, database instances, etc. might change. Ant also includes flow control (if, etc.)
Some things I've seen ant do:
Compile code
Use version control to checkout the latest version or to tag the version being built
Run sql scripts to build or rebuild a test database
Copy files from an external resource for inclusion in a project
Bundle code into a jar, war or ear file
Deploy a web application to an application server
Restart an application server
Execute a test suite
Static analysis, i.e. CheckStyle or PMD
Send email to a team to alert them to a build.
Generate files based on information from the build.
Example: I have a jsp in my app that does nothing but display version/build information. It is generated by ant when I run a build, and the production operations team checks this page when they deploy the application to make sure they've deployed the correct build.
In many larger companies (and likely some smaller ones), you'll find that production code is not built by the people who developed it. Instead, the developers may check their code into a source code repository and tag it. Then they give this tag to a build team.
The build team, in a separate (clean) area - possibly on some headless server (i.e. with no GUI) - will then check out the code and run a build script. The build script will be completely independent of the desktop environment/IDE.
This ensures that nothing which happens to be on any one developer's computer is "polluting" the build. (Or, more likely, nothing outside source control is required for the system to work!)
So most software you use will never, ever be built from a developer's desktop.
PS. You might also want to look at the idea of Continuous Integration
The short answer is that Ant is a great way to create a complete project build that is independent of any particular tool any developer may be using. Without an independent build, things can go haywire quickly - especially for large project teams.
And now for the long answer... I have been brought into several projects without any sense of an independent build. On one project, there was one guy who was not a developer that was tasked with building and deploying the software. He had created 147 separate windows batch files to compile each EJB, each servlet, and each client component. There was no error checking for this build. All log messages, including error messages went to standard out. It was up to him to manually recognize by reading this log which exception or message printed was a normal and which message was an error. He also had to deploy this software he just built. Deploying was equally as complex since there were several load-balanced tiers. Each module had to be placed in the right place manually with options setup to match downstream and upstream tiers. Building and deploying this software took him at least 3 days using this method. Of course, only then could anyone determine if the build "worked". Usually, after this period all the programmers would scramble to debug the build. Programmers would say my module works fine in my IDE. I just click run like this, see?
Indeed, the individual software modules usually worked, but the build and deployment was horribly ineffective. And just as bad, it was equally as difficult for anyone to deploy a build to more than one environment. Management would say, ok you now have this build working in our regression testing environment. Now deploy that same build in this other environment so the sales guys can demo up and coming software. That should be simple to do, but it also took at least 2 days, followed by a "debugging the build" period. Builds and deploys were never simple and never accurate. It really slowed the project down.
Anyway, we replaced this entire procedure with a complete Ant based build and deploy mechanism. The end result was that a complete build could be created and deployed in less than 30 minutes, completely automated. The QA guy managing the builds and deploys could keep a whiteboard of which environment had which build deployed to it and which group was using that environment. This was something that was just not possible with the old system.
Ant is for automating software build processes:
http://en.wikipedia.org/wiki/Apache_Ant
Ant allows CRISP (complete, repeatable, informative, schedulable, portable) builds. You can find great info on it in this presentation by Mike Clark and in his book, Pragmatic Project Automation.
Ant is a build tool, akin to makefiles (albeit with a very different syntax in XML). If you're only using Eclipse it's fine to stick to that and you can always convert an Ant build file into an Eclipse project (Eclipse's launch configurations are then, if I remember correctly, the equivalent of Ant's build targets).
If you want to deploy the source code of the application and allow others to easily build or set it up, automating that using Ant is probably not a bad idea. But it's usually not a consistent experience for users or at least I haven't seen much consensus on what targets should be there and doing what so far.
Ant may also be used for regular automated builds (you wouldn't want to hit Run in Eclipse every night, right? :-))
If there's one close to you I think you'd get a lot out of CITCON, the Continuous Integration and Testing Conference. You get to talk with lots of people about the benefits of automation applied to building and testing software.
Basically people use Ant (with other tools) to automate everything they want to have happen after a commit. The basic advantages of such automation are faster, better and cheaper.
Faster because things happen right away without waiting for a human to get around to it.
Better because computers are really really good at doing the same thing the same way every time. (Humans tend to suck at that.)
Cheaper because you have fewer mistake and the mistakes that occur are caught sooner and therefore cheaper to fix.
You are also referring to the ""Export ant buildfile".
If you write your own Ant script for building your application outside eclipse, you can write your own targets that use the Ant task to delegate to the generated build.xml.
Also, you can configure a project's 'builders' (project properties » Builders) to run any script (ant or otherwise) you want when you build the project, manually or automatically.
Joel (Spolsky) has a great article on "The Joel Test." Many of them revolve around being able to do important things often, quickly and reliably. One of those things is your build.
Eclipse is using ant for building, running, deploying, ...
"Ant is a Java-based build tool. In theory, it is kind of like Make, without Make's wrinkles and with the full portability of pure Java code." (from link text