I'm fairly new to aspectj. and actually need to use it because a feature in spring needs it in order to work.
One thing i don't get. i see that the installation of the aspectj is via eclipse.
so apparently post installation - all my src code and jars are still the same.
so what exactly am i installing? I mean, my project is comprised of jars + .class files so what difference does it make if i install a plugin in my IDE?
p.s I tried to install it but all the installation of aspectj are through maven and I Don't use maven.
there are kind of supporting tools for eclipse that ease aspectJ development (e.g. it shows you weaved pointcuts etc).
AspectJ itself has several options of how to "enrich" your code. You can use compile-time weaving, which modifies your class-files. or you use load-time weaving, in which case aspectj modifies the bytecode during startup of your application.
either way, after weaving, your code depends on the aspectJ-runtime library, so you need this in your classpath too.
If you use maven, you add aspectj-stuff to it, if you dont, you add it to eclipse itself (which is the plugin for, i guess). just install ADJT and you are up and running.
Related
I am using eclipse and having difficulties in finding the related source jar files (including recursive dependencies) manually and linking each one of them to the 3rd party jars in the project class path. I need the source to understand the 3rd party functionality better.
What is the simple way to address this issue?
Your problem is twofold:
First, you have to get (read: download) all the source jar files you need.
Second, you have to tell Eclipse how to find the source jar for a given library.
If you create an Eclipse application (a product or plug-in based on Eclipse Platform or Eclipse RCP) which uses OSGi-Bundles coming from a p2 repository, and if the p2 repository contains the sources, you can usually install the "SDK" feature of the respective project to get the sources.
However, from your question I guess that you are developing a Java application (without OSGi or Eclipse runtime). In this case, I know of no builtin feature of Eclipse which could download and attach the source code for your library jars.
As Phantom Reference said, the best way is to use a tool which is able to download all the referenced jars including their source automatically. And, yes, Maven seems to be the tool of choice, because of its automated dependency management and resolution features.
BTW, if you don't want to use Maven (e.g., because you don't know it and you don't have time to get into it), you could still manually use a Maven repository to find the source (and binary) jars of most common 3rd party libraries there.
Have a look at http://search.maven.org.
I suggest you to move to maven build tool if you are not using it already.
You can configure the maven plug-in in eclipse to do this job for you.
Here are the commands to get the source code as well as the Javadocs by maven itself from command line.
mvn dependency:sources
mvn dependency:resolve -Dclassifier=javadoc
Here is the screen shot from my eclipse Windows --> Preferences that shows how to configure Maven to download and attach the source as well as Javadocs, all automatically. Hope this helps.
I have configured a project to use scala/maven/Eclipse. Because I need a scala library on the build path and scalatest also uses its own scala library I receive this warning :
More than one scala library found in the build path, all with
compatible versions. This is not an optimal configuration, try to
limit to one scala library in the build path.
I don't think I can remove this warning as I need both libraries - one for Maven, the other for Eclipse. This doesn't seem to be causing any problems so will I just have to accept it? Is there an alternate configuration which uses just one scala library for Maven & Eclipse?
If I remove the scala library from the project I receive the error:
Cannot find Scala library on the classpath. Verify your build path!
For some reason Eclipse requires the scala library to be on the build path even though it is already available as a Maven dependency.
There is nothing to worry about. Eclipse warns you that you have several scala-library.jars on your classpath, but as long as they are the same version, it doesn't matter.
If one of them diverged (for instance, by bumping the Scala version number in your pom file), you'd be in trouble: depending on the classpath order, the IDE will pick up classes from one or the other, and you might get different results when building on the command line.
Coming back to your setup, you could
remove the Scala Library classpath container from your Eclipse projects, leaving just the jar that maven adds.
ignore the warning
Venturing a guess here, are you using the Eclipse Indigo pre-installed with Scala 2.9 and the corresponding Scala plugin? If that's the reason you need to use that library, perhaps consider using Eclipse Juno? That's what I use and it works quite well with both the milestone and the nightly builds
Does anybody have experience working with JavaRebel, specifically for a large web application built using Maven? There is a JavaRebel plugin for Maven that seems under-documented, does anybody have comments on how it works, can you really update one class in a Multi-module Enterprise Project and have it "automagically" change on your Server?
Are there any issues with different IDEs and this setup? For example NetBeans will not let you compile one class at a time in a Maven project (from what I can tell).
Disclaimer: I work for ZeroTurnaround.
JRebel (formerly JavaRebel) installation involves the application configuration file "rebel.xml" and modifying the container startup command line.
The Maven plugin is used to generate the "rebel.xml" file, that is used by the JRebel agent running in the container to find the files in the workspace. This allows to use IDE building to compile .java files and skip the Maven build process, as the changes to files will be picked up from the workspace. However as it relies on the IDE to compile the classes, it does depend on the IDE ability to compile efficiently. I know for sure that Eclipse will compile classes one at a time and am fairly sure you can configure NetBeans and IntelliJ IDEA to do the same.
In addition to the Maven/rebel.xml configuration you also need to configure the container startup command line. You may also need to install and IDE plugin or do some additional configuration to have the best expirience with JRebel. Following through the steps of Installation manual ensures that.
Hope this helps.
Disclaimer: I've not actually used this plugin myself.
This tutorial implies that JavaRebel works well with Eclipse 3.4. If you are also using m2eclipse it should work ok with Maven projects as well (as long as you ensure that Maven and Eclipse are compiling to the same target folder so the Eclipse incremental compiler can be used to modify the class file).
According to this post, you should configure the javarebel-maven-plugin to generate the rebel.xml (used to mount external folders to the application classpath). There's also a general installation guide you may find useful.
I'd be interested to find out about any automated processes that people have for ensuring that the project classpaths for the ant and eclipse configurations are in synch. In my case, I want the classpath defined in the ant build file to be the master configuration, since its used for our production builds. As part of the build i'd like to add an ant target that will verify that the eclipse classpath is up to date, or at least indicate differences between the two classpaths.
I'm aware of ant4eclipse but its focus is in the opposite direction, ensuring that the eclipse classpath is master and that the ant build reuses the eclipse path. I like the idea behind AntAndEclipse but am wondering are their ant other tools in this space that i'm not aware of.
You solution at a previous company was to have ant invoke Eclipse to do the compiles as described here:
http://www.eclipse.org/articles/Article-PDE-Automation/automation.html
I'm not aware of any ant tools which can do this but I've switched from ant to Maven a few years ago and never looked back. You can use the "Maven integration for Eclipse" to make Eclipse use the Maven classpath.
As of today, I'm not 100% happy with the Eclipse plugin, though. It's a bit slow and due to the different philosophy of Eclipse and Maven, some operations behave strange. For example, Eclipse doesn't differentiate between a "production" and "test" classpath, so you can get compile errors in Maven when everything looks great in Eclipse.
My solution was to use the plugin to keep the classpath in sync and compile from the commandline.
there is an ant task to do xml transformations, we used that task to create the classpath in our build file. It was a little trick to get the XSL right but once it worked it was great
Did you evaluate Apache IVY? Currently I am building a Continuous Integration environment at our place and we use IVY to handle our dependencies. There is a eclipse plugin that takes the dependency configuration of eclipse and uses it as eclipse classpath.
Currently this solution looks quite promising.
My team wrote an Eclipse plug-in to add a new type of library to the Java Build Path->Add Library option in the project settings. This custom library type allowed both Eclipse and ANT to reference the same canonical list of dependencies.
Nowadays, I'd probably look at IVY for doing the same thing if I was locked into using ANT, rather than writing my own.
You need Ant2Eclipse.
There seem to be two rival Eclipse plugins for integrating with Maven:
m2Eclipse
and
q4e.
Has anyone recently evaluated or used these plugins?
Why would I choose one or the other?
Side by side comparison table of three maven plugins.
There is only one point where q4e is actually better: dependency viewer. You could see the dependency tree, manage your dependencies visually and even see them in a graph. But, m2eclipse works in a better way, specially because you can create you own build commands (in the run menu). q4e comes with some predefined commands and I can't find where to define a new one. In other words, m2eclipse is more friendly to the maven way.
I have been using m2Eclipse for quiet some time now and have found it to be very reliable. I wasn't aware of q4e until I saw this question so I can't recommend one over the other.
My 2cents,
I am using eclipse for some months now with m2eclipse integration. It's easy to use and straight forward. Once you associate your project to maven and update the dependencies using m2eclipse, any change to pom.xml are reflected to entire project, even Java version definition causes it to be compiled in right JRE (if you have it installed, and properly configured into eclipse.)
Another advantage I found is the maven plug-ins are easy to use integrated with eclipse (jetty being my best example, again, properly configured you can easily integrate maven, jetty-plug-in and Eclipse Debugger)
Compilation, packaging and all other maven features are equally easy to use with a couple clicks or shortcuts.
About q4e I have been reading a lot of good stuff about it and seems the next versions will do a lot more than m2eclipse, with a better dependency management and even visual graphs (!) but the general opinion is that m2eclipse is still better than q4e but q4e is getting better each new version and maybe will surpass m2eclipse soon.