As I'm quite new to Java, I would like to know the proper procedure of installing new libraries (those that are no available in my linux dist repositories).
Where should I place them? and how to install them?
For instance, I downloaded openCsv (http://opencsv.sourceforge.net/), and I have no idea how to install it.
Java libraries don't really need to be 'installed' like other applications. All you need to do is put the jar file in a specific location, and add the jar file to your classpath. How you do that depends on the linux distro you are using. If you are making a web application in eclipse, you can drop the .jar file in the WebRoot/web-inf/lib folder, and it will be bundled in with your project.
Be sure that the path, which you place the libaries at, is set in the $CLASSPATH Environment Variable.
For Eclipse: Project -> Properties -> Java Build Path -> Add JARs...
It's up to you really - I use /opt/javalib, but you might consider a directory in /usr/local as well.
You can store them wherever you wish. You can store them within the JRE distribution directories, but I wouldn't recommend that.
Instead I would store them per-project (so you can have different versions for each project easily - some libraries have different names for each version, some don't) and adopt a standard such as a lib/ directory. That way you can have standard build scripts (Ant etc.) that can operate in the same way (if you're using Maven, then there's a standard place per-project - src/main/resources)
You could use Maven to manage any dependencies to those libraries.
Maven will automatically download all needed JAR files and put them in a local repository (the location is configurable).
This makes upgrading to new versions of various libraries very easy as you just declare the version you want and Maven does the rest.
Beware: Maven is something to get used to and the initial learning curve is steep.
The rewards come if you have everything set up properly and maven takes care of compiling, packaging, distribution, site creation, release management etc. etc. etc.
Related
I'm creating a Java project which includes a few libraries written by myself. However these libraries are not finished and sometimes require some edits. Because I'm working by myself, I find this more efficient than finishing all libraries perfectly before using them in my project.
My question is: is it possible to automatically rebuild a modified library when building the project which uses it?
Subquestion: what is the optimal configuration for my purposes? Should I export libraries as jar and copy them into the final project or should I configure buildpaths of my project to retrieve them in their respective folders?
Subsubquestion: is it correct to use .jar libraries in the same way that one uses dynamic libraries in c++?
If you have Eclipse set to "build automatically", it'll take care of rebuilding the library projects whenever you make changes, as you go along. You should set your client program to depend on either the Eclipse projects (if doing everything inside Eclipse) or the Maven artifacts (if using m2e). I strongly prefer using Maven for all my Java builds, but it might be overkill for something small. Whatever you do, don't manually export and reimport the libraries.
All libraries in Java are dynamic, and a C++ .so or .dll is the basic equivalent.
This is getting to me a bit.
What should be a straightforward and well worn procedure to do something all users need to do is anything but straightforward.
I made the Java class I want to add to all new Java projects into a JAR file.
And I got it into the JRE folder using Window > Prefs > Java > Installed JREs, etc.
But come runtime, the Java interpreter just doesn't see this class as attached to my projects.
Anyone know how this pesky one is fixed ?
I'm using Eclipse 3.6.2 Helios and JRE 7.
The JRE isn't really intended to be extended in this way. If you must store your shared libraries in the JRE, the ext folder should be used, rather than the top-level JRE folder. However, even this is usually a bad practice: Is putting external jars in the JAVA_HOME/lib/ext directory a bad thing?.
To add dependencies to your Eclipse projects, use the project's build path. To add dependencies at run-time, use the Java class path.
I would create a userlibrary and add the lib to the project setup. http://goo.gl/pEoto
Consider to use Maven to manage your dependencies.
I have inherited a big project with several subprojects.
all of them use several jar files, all of them located under each project's lib directory. I want to take all the projects and migrate them to maven, but dependencies are a problem (too many of them), some of them are commonly used libraries (apache projects, xerces, jms, etc) and others are not.
is there a way to autogenerate maven dependencies for those jars that can be found on public maven repositories. for example, see that my project use the spice-jndikit-1.2.jar file and automatically get the appropiate depedency with group, artifact and (if possible) version?
thank you
I wrote a groovy script to generate a starting set of Apache ivy files.
https://github.com/myspotontheweb/ant2ivy
In my case, I wanted to "Maven-ize" my ANT builds without switching completely away from ANT.
It is feasible to extend this code to generate a Maven POM, if people were interested in this feature.
You can convert a project to Maven using the m2e plugin, but this erases your jar references, and should not be used.
I doubt that such a thing exists since typical jars (unless themselves built with Maven) don't have the necessary information to correlate the groupId, artifactId and version back to a repository to get the proper path.
You might be able to write something that parses the file name for the name and version, but you still have the package-based path to figure out.
If you're building using Ant, you might also consider using Apache Ivy, and its file-system based resolution (very fast and easy to configure), to get you started, and slowly role over to the Maven repos for the artifacts, this way you're not spending a lot of time up-front finding Maven dependencies.
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.
When sharing a project with team members through version control, it is customary to include the .project in the source under version control. This makes sure that others on the team get all the dependencies and resources for the project. But the .project uses full/rooted paths to the resource, and not all members of a team will be working in the same environment. Even if all the members are on the same platform, the paths can often be in the user's home directory.
For the .classpath file, we can get around this problem by using build path variables. Each member defines the path to location of dependent libraries on their system, and the .classpath only refers to the variable.
This is a particular concern for Grails project - when we add a plugin, it updates the .project accordingly.
IMO resources themselves should not be part of the project at all. There is excellent plugin called m2eclipse which simplifies such tasks using Maven. It will immensely simplify your dependency management. All you'd have to keep in your version control system, besides your source code, is project configuration (pom.xml) - all the dependencies will be downloaded and cached automatically no matter what environment developer works in. There a lot more advantages in this approach - just read up on it :)
UPDATE: Just noticed "grails" tag on your question. if you're using Groovy - Maven can be replaced with Gradle. STS is probably the best Eclipse build to use if you're coding in Groovy. Next version of STS will have Gradle support.
General Approach
As others have mentioned, you should not keep the IDE files in VCS, you should keep an IDE-agnostic description of the project in VCS and generate the IDE-specific project files from them.
Java-Maven Example
Keep the pom.xml file(s) in VCS and generate the Eclipse files by running mvn eclipse:eclipse
Grails Example
A Grails project is described by application.properties and grails-app/conf/BuildConfig.groovy. These files are present in every Grails application. You can generate the Eclipse project descriptions from them by running:
grails integrate-with --eclipse
This command also supports other tools such as IntelliJ and Textmate
I don't think its standard practice to include the project file. I personally tell my VCS to ignore all IDE files, and just use VCS for the source. I include at the root level a README telling others how to configure the project (e.g. jars are in lib)
The resource links feature that you are referring to also has ability to use path variables. These are defined under Preferences -> General -> Workspace -> Linked Resources.
You could try keeping the project files in a shared Dropbox with an agreed upon path for each developer.