I have a Java application and created a JAR file and deployed it.
The App uses external JARs such as the Log4J JAR. When creating my JAR file, how do I include all external dependent JARs into my archive?
In order to get my App working, I'm having to copy the Log4J JAR into the same directory as my own JAR which kinda defeats the purpose of the jar. Wouldn't it be more elegant to have 1 single JAR file to deploy?
If you use Eclipse, You can extract all included files into one runnable jar like this:
Right click on your project name from Package Explorer and select Export.
In Export screen, select Java -> Runnable JAR file and Next.
Fill in the Runnable JAR File Spec screen and Finish.
You can choose whether to package dependency jars as individual jar files or extract them into the generated JAR.
You could use something like One-JAR to package your Java application together with its dependency into a single executable Jar file (One-JAR uses a custom classloader to make JARs nesting possible).
You have to expand the library jars into the same place where your compiled classes go, then make a jar from that. Depending on how your build process is set up, there may be multiple ways to achieve this. It's not rocket science - a jar is just a zip archive with a META-INF directory at the root level.
Keeping JAR separate is better as it is easy to upgrade only the specific JARs to its new versions without touching any other configuration. As of your issue of having to copy each file to same location as of your JAR, you can always use Java CLASSPATH and include any JAR to your application's class path.
A JAR is not itself capable of nesting other JARs, as you discovered.
Traditionally, one would distribute a ZIP archive or other installer that would unwind the application JAR (yours) as well as any support JARs in the appropriate location for classpath access. Frequently, then, the application was invoked through a script that invoked the primary JAR and created a classpath that listed the support JARs.
As other posters have noted, you have some options to create a super-JAR if that's what you want.
You can use Maven + assembly plugin (http://maven.apache.org/plugins/maven-assembly-plugin/)
BTW, probably that's not the easiest way, if you did not work with maven.
Related
I have created a JavaFX application using NetBeans IDE and below is my folder structure.
I want to a build a single jar file including all dependencies for this jar to work properly.
This jar requires testplanner and batch folder from project root directory and files inside dist folder to work properly.
How can I package all this to a single jar file?
Theoretically JAR files cannot contain dependencies within, as java does not support it out of the box. WAR and EAR archives can. What You want to do is not standard, but is named fat jar. Fat jars are used i.e. by spring-boot maven plugin, but you could try this:
https://dzone.com/articles/how-build-fat-jar-using
And some more explanation:
NetBeans - deploying all in one jar
Use tecreations Deploy. Put all your sources into a path declared as Tecreations.getProjectPath(), run BuildAll to create your corresponding classes, put your jars in projectpath/jars and select the appropriate settings, whether to include jars, sources or classes. Select your main class and click Deploy. Unsigned and signed output jars are produced in user/Documents.
Download: https://tecreations.ca/java/downloads/release.
This question may be theoretical but I could not find any proper solution.
Suppose I am making a module which uses 3 jar file(hibernate,log4j,jackson).
Now I want to compile my module and create a jar such that my module can be used by any other module and that module should not require the three jars(hibernate,log4j,jackson) to again.
i.e my module jar file should not have any dependencies.
I am using eclipse.I am able to create a jar(project->export->jar) but it does not include the jars in it
Guide me how can I do that.
Is apache ant of any use here?
Eclipse's Runnable Jar Wizard
Eclipse's Runnable Jar Wizard (File → Export… → Java → Runnable Jar File) allows developers to create executable jars from an existing run configuration:
The wizard includes 3 options for handling dependencies:
Extract required libraries into generated jar: unarchives library
dependencies and repackages them into your executable jar. This
option has the advantage of simplicity and does not require a custom
class loader. However repackaging library jars can cause other
problems and does not preserve the signatures of signed jars. This
option may also violate the license terms of the libraries you are
using.
Package required libraries into generated jar: creates a "fat jar"
with a custom class loader. The resultant jar contains
the application's classes and resources
library jars required to launch the application
a small custom class loader that knows how to find jar libraries inside another jar archive
Copy required libraries…: creates the application archive and copies
any required library dependencies to the destination folder.
I think the second option suits your present purpose.
You will need to include all classes from your dependencies into your jar file.
Since a jar file is merely a zip file, you can use any archive manager such as Winzip to explore them, then copy the contents of the jars you depend on into your own jar, taking care to keep the directory structure intact.
That way you have everything in one jar.
I made an executable jar that depends on other jars with the command prompt using the format
jar cvfm MyJarName.jar manifest.txt *.class dependentJar1.jar dependentJar2.jar
The jar was made properly and everything seemed fine... But when run, it gets runtime errors because it can't find the class files that my project refers to. Exploring the created jar, the other 2 jars that it depends on are in there just as they should be and they are listed in the manifest.mf class path, but for some reason java is dumb and doesn't actually look inside those jars.
When those 2 jars are in the same directory as the owner jar, java is able to find them and it works fine. But I don't want this; I want those jars to actually be INSIDE it. What's the deal? How can I make an executable jar with other jars inside it work?
You can use something like OneJar or jarjar (or any of several others) to pack up everything inside of a single jar.
If you're building with Maven you could use the Maven Shade Plugin.
You could use a custom classloader like JarClassLoader that will allow precisely what you want.
I don't think you could. Maybe it's somehow possible with customized classloader, but not from-the-box. Use maven shade plugin.
If you use an Ant Builder in Eclipse and put the referenced jars in a library accessible to your project, Eclipse will extract the necessary classes and include them in your distributable jar file.
I'm using the Eclipse "Export... Runnable jar file" feature to package up my Clojure+Java application for deployment.
This works great, magically including various resources and Clojure source files etc.
The one issue I have is that various libraries I have get included multiple times from the "lib" directory dependant projects, e.g. I get four versions of the Clojure jar file due to other projects on the build path that also use Clojure.
This issue is needlessly tripling the size of my .jar file!
Is there any way to easily eliminate these duplicates other than manually deleting from the generated jar?
If there is a natural dependency graph to your projects, I would change your eclipse project settings such that only one project has the jar on the build path and it exports (by export I mean from the "Order and Export" tab in the Configure Build Path dialog) that jar for other projects to see. The other projects then have that "core" project on the build path. I believe this should naturally take care of your problem.
Edit
One comment I have is that having a jar within a jar is rarely a good idea. I would either reconsider packaging it all into a single jar (unless the point of the main file of the jar is to extract its own contents into a folder) or maybe explore the possibility of using the "Extract required libraries into generated JAR" option.
i have created a java application which uses data from its config folder and , it also uses third party jar files those are located in lib folder, could anyone tell me how to create jar file for this project with the content stored in config file and lib folder.
i tried creating jar using eclipse export functionality. when i run this jar file, it says it can not find the third party libraries that i have used for this project and configuration file.
thanks in advance for any help
You can create a Runnable JAR in Eclipse 3.4+ in the Export wizard selection dialog (right click on a project and go to Export...) using an existing launch configuration which will incorporate the libraries or repack them. Config files should be readable from the same directory as the runnable jar is located. If you need any help with loading these in, just ask :)
(source: eclipse.org)
You have two options
include the stuff in the third-party jars in your jar
provide access to the jars on the classpath when you run your jar.
Both have their benefits and their drawbacks.
Java does not support putting JAR files inside executable JAR files, so you can't just put your third-party library JAR files inside your own JAR - Java won't be able to find them.
If you don't want to distribute your application as a whole bunch of JAR files, you can use a look such as One-JAR which will build a JAR file for you that contains your own classes plus the classes of the third-party libraries that you're using.
To learn more about how to package a program in an executable JAR file, see Packaging Programs in JAR Files in Sun's Java Tutorials.
If you use netbeans just by click on "build" a jar file will show up in the "dist" file in your project directory