I've downloaded the code for an Eclipse plugin. The code uses log4j, but it doesn't just use it as a library (referred jar), but as a "bundle". So it doesn't compile because of the following reason:
Bundle 'org.apache.log4j' cannot be resolved
I'm not really sure what's the correct approach to solve this. I know how to add jars to a project, but how do I add "bundles"? Is it something I need to add to the entire Eclipse host?
I "solved" this by creating a new plugin project with no code but with the log4j jar included... but that doesn't feel like the right solution.
I've also found some places where "log4j bundles" are published, e.g.:
http://ebr.springsource.com/repository/app/bundle/version/detail?name=com.springsource.org.apache.log4j&version=1.2.16
http://download.eclipse.org/tools/orbit/downloads/drops/R20110523182458/
But I'm not sure if that's what I need, if it matters where I get it from, and how to "install" it.
I assume you are using the Eclipse Plugin Development Environment (PDE). In this case, the log4j bundle needs to be imported into the "Target Platform".
The Target Platform is like a repository of bundles (i.e. plug-ins) that replaces the "classpath" in traditional Java development. You can find the location of the target platform and modify it by going to Preferences -> Plug-in Development -> Target Platform.
HOWEVER before doing this I strongly recommend you take some time to learn a bit about what you are working on! If you want to develop an Eclipse Plug-in you should at least learn what a plug-in is, and how its dependencies work. If you read a bit about the subject you should not have to ask such an extremely basic question on Stack Overflow... it is covered in all the introductory tutorials and FAQs.
Related
I'm trying out Java 9 Jigsaw module system (no module experience yet) and would like to use it for capsuling the classes within my project, but it's confusing.
According to this article it should be possible to have multiple modules within ONE project. I made a new project in Eclipse Oxygen (Java 9 is supported) with the same structure as shown in the article. But Eclipse keeps telling me that I must not have more than one module-info.java in a project.
I really don't know how to tell Eclipse that it should use the "multi-module-mode". And I really would appreciate not having to create a new project for every single module.
This works:
This not:
But according to this article something like that should work:
And how about deployment of a modularized project with Eclipse? There is nothing to see about the new jmod extension. Do I still export it as a runnable JAR file like before?
Notice that my questions refer to working with the IDE (no command line, I mean with an IDE that should be possible, right?) Thank you for enlightening me.
Currently, Eclipse requires you to create a separate project for each module (e. g. because each module has its own Java Build Path).
To understand this design decision, consider that Java modules correspond to OSGi bundles / Eclipse plug-ins and it has always been to have a separate project for each bundle/plug-in. If you come from the Maven world, you would probably expect a deeper folder structure instead. But modules are self-contained and combining several modules into one project would only add an additional folder level without meaning. However, Eclipse supports nested projects and so-called working sets if you need an additional folder level.
Exporting modules as images is planned for Eclipse 2019-03 (4.11), on March 20, 2019 (see Eclipse bug 518445). Exporting modules as JARs that can be used on the modulepath (-m) already works (see my video).
I don't know if this question is still open for an answer, but you can solve this problem by simply removing all source folders on the build path. At least this works for Eclipse 2021-12 version.
As you can see this is a demo project from the Official Gradle Guide Book and it has multiple modules. Each module has its own module-info.java.
project structure in IntelliJ IDEA
If I open this project in Eclipse it will give me the 'duplicated entries on module-info.java' error.
Eclipse shows the error
But if I delete all the source folders on the build path, the error is gone and the project can be built and run without problem.
project properties: Java build path
The only problem is that you have to build the project with Gradle so that it will produce the .jar of each module and you have to include them in the libraries later.
include all the .jar in libraries
I think this is probably the same solution mentioned by howlger above.
I've noticed that in eclipse if you Right click on a project -> Grails Tools -> You have the option to 'Download Source Jars'.
What is the point of this and what are some common reasons as to why you would want to do this?
Grails 2.2.3
Edit:
I'm not even sure what grails does instead of that.
Many (most) libraries (JARs, "artifacts" in the Maven terminology) publish a sources archive alongside their binary artifacts in the repositories. This can be useful for Eclipse to show you the Javadoc and source code when you're using the library in your projects. As #JonSkeet commented above, it's very useful to have source code available directly in the IDE when using a library.
By default, Grails does not download the sources for artifacts; this option triggers it to do so and attach the sources to the binary JARs.
Agreed with E-Riz.
Here are the reasons I use the sources:
i want to have a deeper understanding of how the library works when debugging my own depending code
i want to find a possible bug in the library, so I can fork it and apply my own patch. i will possibly share this with the maintainers as a pull request if I'm willing to spend that much time on it.
i want to find out what logging systems it uses that might be poorly documented, so I can see better what their code is doing during runtime, to troubleshooting complicated problems.
I am trying to get started with Eclipse SCADA and import the projects from their git repository.
I have cloned the following projects:
org.eclipse.scada.external
org.eclipse.scada.utils
org.eclipse.scada.base
org.eclipse.scada.protocols
org.eclipse.scada.core
org.eclipse.scada.releng
For each project I did mvn verify in the parent folder and imported the projects in Eclipse. I also changed target platform. However, I still seem to have problems with their dependencies.
Any help would really be appreciated.
Actually the Eclipse SCADA java projects are not developed with "Maven first". So you should disregard maven completely while in the IDE. The maven build is basically only used to build the project unattended.
The issue with the target platform is more complex. We were a bit sloppy in providing a always working target platform (and it is actually difficult to keep them up to date, since the versions of the bundles are fix).
I made a target platform file for the current version, you can find it here: https://gist.github.com/CptMauli/ec6eda37734f0108510f
To make it work properly please download a classic eclipse put it somewhere and create an environment variable ECLIPSE_432_HOME which points to it. Alternatively you can just change the first entry in the target file and point it directly to it.
The reason behind it is, if you would use your own eclipse installation, it is possible that bundles installed there conflict with bundles provided in the target platform or from your workspace. This is actually mostly not even a problem when compiling, but as soon as you start a client or a server, Eclipse will complain about duplicated bundles.
If you have any more questions please go to our mailing list: https://dev.eclipse.org/mailman/listinfo/scada-dev
or our google group: https://groups.google.com/forum/#!forum/openscada
or write to me directly at juergen dot rose at ibh-systems dot com
Is the file .settings/org.eclipse.jdt.core.prefs part of the project or is it part of my personal eclipse configuration?
Should I add it to version control?
Yes, you should. If this file is not under version control, then you cannot create reproducable builds of the same project, because it is no longer self contained, but depends on your specific Eclipse installation and its settings.
If you import this project into another workspace (on your or any other machine), it may behave completely different, as the compiler compliance settings, the compiler warnings configuration and a lot of other stuff is suddenly missing or different. Chances are high that such a project suddenly shows warnings/errors in the new workspace, while it was completely fine before.
Note: This all also requires that you actually configure all Java related settings in the Project properties. Never use the Java compiler settings under Window -> Preferences if you want to have self contained projects.
Just to give a concrete example: If you have configured your projects compiler compliance level to Java 6, because you are using Java 6 specific features (like Override annotations on interfaces), then the project will create a lot of compile errors on other peoples machines. This is because the default compiler compliance level in every Eclipse workspace is Java 1.5, and in Java 1.5 that Override annotation is simply not allowed.
This doesn't have anything to do with whether you are developing closed source or open source, as indicated in the other answer.
Contrary to #nitind's opinion, no. You should not put any IDE-specific settings under version control. Except you are developing IDE features or plugins.
In case you really have mandatory team-wide IDE settings, putting them under version control would be a good idea, but IMO having mandatory team-wide settings is not a good idea in itself.
For all other cases, shared IDE settings are bad for portable builds, even with the same IDE, and useless at best for users of other IDEs.
EDIT: I should differentiate, depending on the target group of your project. If you are developing a closed source product in a team that works with eclipse, then keeping these preferences under version control is helpful and a good idea. If you are developing a library, closed or open source, or an open source project, I consider ignoring the preferences more appropriate and polite.
EDIT2: I'm afraid #Bananenweizen is misunderstanding what I am trying to say.
I know that these settings are the eclipse compiler settings. They are still IDE-specific in the sense that they won't have any effect in Netbeans or IntelliJ as they won't have any impact on ant or maven builds from the command line.
Yes, leaving these setting out of version control can bring you many red wavy lines in eclipse on a different machine. It won't, if it's a maven project with a set source level by the way, I'm not sure about ant.
Eclipse is not building the projects by itself - it builds them with ant if it's an eclispe or an ant project, or with maven if it's a maven project. Both ant and maven have specific settings for the source version that do not depend on IDEs.
And this is where these settings ought to be - in the build file. And the build file should be under source control. The exceptions I mentioned earlier still apply.
EDIT 2020.03.15 #howlger informed me that the usability of these formerly eclipse-exclusive files has improved. They can be used in VSCode and maybe IntelliJ. This improves their chances of being useful across IDEs and may change your decision towards sharing them.
IMO, the files are mixing concerns. While I support source level and code formatting as being part of the build, I consider issue highlighting rules, save actions and similar concerns to be out-of-scope. If possible, I separate those, sharing the former by putting them into the build definition, but not the latter.
Here is the problem with putting it under version control....
If you import and open a project, Eclipse insists when IProject.open(...) is called on touching the file in the .settings folder... and this is before you can register the team provider on the IProject object. That means validateEdit won't fire and you get annoying errors whether you click "yes" or "no" on the popup asking "do you want to make it writeable?" That's all well and good for optimistic file-locking providers, but no so great for the "pessimistic" ones. For us this is just been yet another eclipse annoyance.
If it's up to me, there is no way I'd put these in source control.
The answer is "yes" and here you find the motivation for it and the proper way to do it: watch the talk "Committing IDE meta files: misconceptions, misunderstandings, and solutions." or look at the corresponding slides from EclipseCon Europe 2015 by Aurélien Pupier #apupier (Senior Software Engineer, Eclipse specialist).
There are a few options for developing modules for Netbeans 7.0.1 RCP. I haven't found any clear comparison of them.
So I would like to know which of them is the easiest to:
develop
install by user (e.g. user could choose proper jar with module
from a repository )
Which makes to write less non-reusable code (e.g. when you want to make web application of used classes later)?
Which is the most popular?
The easiest way is to use the traditional Netbeans way - build nbm's. This is well tested and good feature. After building module you will get the "nbm" file with all needed info inside (additional jars, settings, etc.)
You can use "Module Update" features from Netbeans.
The other way is to build modules as osgi bundles.
This feature was introduced in 6.7 version and up to now it has some problems.
First of all, bundle in normal understanding is one jar. If your bundle depends on other jar (f.e. apache-commons:beanutils), you will need to pack this jar into your bundle jar (using maven-bundle-plugin) or to install "beanutils" as independent bundle. The first solution is not the best, because if in the future another bundle wants to use "beanutils" you will need to link new bundle with old one, even if they don't need this. This cause high cohesion between modules. Or you can pack "beanutils" into your new bundle, but this can cause classloading issues in osgi-framework.
So, if you need to install netbeans module, you just install one nbm file and that's all.
If you need to install bundle, you need to install all dependent bundles separately beside yours bundle.
Another things are, for now you can't configure osgi-framework, which embedded in netbeans and process of loading bundles has some differences from loading standard netbeans modules which can cause some "strange" issues.
I'm sure that guys from netbeans will fix this issues and they are moving in right direction, but for now, if you don't need bundles, don't use it.