I am trying to package a Java project into a runnable jar using Eclipse (version Kepler SR2). The project is using Maven (which has been fored onto me and I don't know much about it). The problem is that the project runs fine within Eclipse, but after export to Jar it doesn't find any of the required resources anymore.
Here is the folder structure:
+src
+main
+java
<packages with source code>
+resources
<folders with static resources>
+test
+java
<unit test classes>
I have also added the resource folder to the build path.
The resources are loaded using
File myFile = new File(getClass().getClassLoader().getResource("resourcePath").getPath());
This line works perfectly fine when executing the program from Eclipse, but it fails with an NPE when using the executable jar that I created with "Export>Java>Runnable Jar".
I have already to use the standard Jar export with the options "Export generated class files and resources" and "Add directory entries" checked. This leads to the same problem, though.
What do I need to do in order to correctly export the resources into the Jar?
Thanks!
Martin
Use maven-assembly-plugin:
Reference:
Building a runnable jar with Maven 2
http://www.javavids.com/video/how-to-create-runnable-jar-file-with-maven.html
Maven's default strategy is to copy resources in a separate "resources" folder and to add that folder to the class path.
When you import a Maven project, Eclipse is configured to treat the “project/src/main/resources” folder as a source folder but to exclude everything from being exported **. The temporary output folder is “project/target/classes”. You can see this in the java build path.
So, when you are inside Eclipse, resources are copied to the right temporary folder and everything works fine.
When you ask Eclipse to build a runnable JAR, it copies resources to the “resources” folder but does not add this folder to the classpath. You can see this if you open the JAR.
You have three solutions (from better to worst):
Use maven to build your runnable JAR. See: Building a runnable jar with Maven 2
Edit Eclipse’s build path to remove the “**” exclusion. This change will be overwritten every time you sync with Maven
Move your resources. See: Change maven's export resource directory
Related
I am trying to add external jars to my Java (without Maven) Project.
But I don't get it to work at all.
The official documentation: https://code.visualstudio.com/docs/java/java-project
says there are 2 ways to do it:
1."You can use the Java Dependency Viewer to add any JAR file to your project."
https://code.visualstudio.com/assets/docs/java/java-project/manage-dependencies.gif
As you can seee in the gif, the dev opens a "referenced libraries" folder.
This folder DOES NOT EXIST for me.
or 2."The other easy way to bring additional JAR files as dependencies is to create a lib/ folder in the root directory of the standalone files and place your JAR files there. Source for foo.jar is automatically detected if there is a foo-sources.jar in the lib/ folder."
https://code.visualstudio.com/docs/java/java-project/lib.mp4
I have the Jar file in the lib\ folder but it still shows me he same error messages.
Are there any steps I am missing?
As it says, place the external jar files in the ...\JAVArpg\lib folder.
So copy them from wherever you have them now. cp ../lib/*.jar lib/ is just an example.
You can use the Windows Explorer. You don't have to copy the files using a command-line.
Recently I wanted to add the nebula shelf to my eclipse plugin. Therefore I added the org.eclipse.nebula.widgets.pshelf.source_1.1.0.201701302244.jar the build path of my eclipse project.
Sadly eclipse can't find the class files inside of the jar, even after cleaning and rebuilding the whole project.
Picture:
Checking the same jar file with jd-gui results in:
Picture:
I exported the *.java files with jd-gui and copied them to my project. Using this method my project built successfully and worked as expected.
Can someone tell me how I can use the jar file without exporting all of the java files manually? Thanks for your help! :-)
Do not use source jars. You can tell eclipse while debugging to use the source jar.
Add the jar to build path: right click on jar -> build path -> add to build path
Don't try to add Eclipse plugins directly to the build path of another plugin as it won't work.
Instead add the plugin to your target platform or import it in to your workspace.
Then add the plugin to your plugin's Dependencies. In the MANIFEST.MF editor you do this on the 'Dependencies' tab in the 'Required Plug-ins' list.
I have a Java project that I'm working on in Eclipse. I have all my code in a src. Eclipse automatically compiles my .java files and stores the .class files in a directory called tmp.
Earlier, I was suing Ant to run my project. My ant script would would compile my Java code, and Jar all the .class files into a .jar and store it into a jar directory. In this jar directory I have some other files e.g. settings.cfg and data.lst. My application needs these files to run but they should not be included in the Jar. They will be deployed along with my JAR and should reside in the same directory. Currently while developing, I have modified and customised my settings and properties files to contain additional information. I don't want these files replaced every time I have a new build as I would like the data to persist across builds. I'm just looking to get the built JAR into the jar directory and execute that. The rest of the files stay the same.
How can I configure my Eclipse so that it always compiles my code, JARs it to the jar directory and executes that JAR. That way, my "extra files" are always in the same place as the JAR.
I'm having a lot of trouble figuring out how to accomplish this.
If you need this feature for fast running/debuging, create new Run Configuration and in the Arguments tab, Working Directory specify the "jar" directory.
The answer was found on another SO post. It was about creating a new "Run Configuration", removing the default classpath entries and adding a the folder containing the JAR i.e. the jar directory and also the JAR file itself.
Here: https://stackoverflow.com/a/1732316/304151
I also had to modify the build configuration a bit. For automatic builds, it used the Java Builder to compile all the .java files into .class files and store it in the tmp directory. I used a custom Ant task to package all the .class files from the tmp directory into a JAR and store it in the jar directory. This is the file that Eclipse executes.
In your project, right click Properties, in "Java build path" menu you can set "default output directory" in the Source tab and make it point to jar directory:
EDIT: I appreciate the suggestions for Ivy or Maven, but this is just not an option for me at this time. I do not have the authority to use those tools. I am simply looking for a way to get my referenced .classpath JARs into a folder inside my project.
I have created a project that uses about 50 external JAR files that I referenced from other projects inside the same workspace.
Thus, my project's directory strucure looks like:
MyProject
src/
test/
Referenced Libraries/
... 50+ JARs
lib/
My project compiles and runs beautifully inside Eclipse. But now I need to add a buildscript so other developers can pull the project down from SVN and run it standalone. To do that, I'd like to place all the JARs that are currently in Eclipse's in-house directory Referenced Libraries and copy them into my project's lib directory which I will JAR-up with the final distribution.
I'm in Package Explorer, and have tried to just copy + paste the files from Referenced Libraries to lib/ and no dice. I get the following Eclipse error:
Cannot paste the clipboard contents into the selected elements.
Anybody have any idea how I can force this copy operation to work? If I right-click any JAR inside Referenced Libraries I see an Eclipse option called Migrate JAR file, but I'm afraid that would cut-n-paste the JARs from their current location to the new lib/ directory. This isn't feasible because there are many other projects that need these JAR files exactly where they are.
Thanks for any insight here!
Have you considered Maven? It's an exceptional tool for situations like this. For file operations it's best to use Navigator view.
I don't find another way to go but to copy yourself the jars into your lib folder, add the references to your lib files (not to external jars on your machine) and upload it to SVN.
EDIT to clarify:
Remove all references from your build path. Now you can't compile the project.
Copy every jar file you need to your project's lib folder.
Go again to build path and add the references to your jars (the ones on lib) one by one. Use the button that says "Add JARs...", not the one that says "external JARs".
Compile, and if everything is fine,
Upload the whole project to SVN.
I'm trying to export a program in Eclipse to a jar file.
In my project I have added some pictures and PDF:s. When I'm exporting to jar file, it seems that only the main has been compiled and exported.
My will is to export everything to a jar file if it's possible, because then I want to convert it to an extraditable file, like .exe-file.
But how?
No need for external plugins. In the Export JAR dialog, make sure you select all the necessary resources you want to export. By default, there should be no problem exporting other resource files as well (pictures, configuration files, etc...), see screenshot below.
Go to file->export->JAR file, there you may select "Export generated class files and sources" and make sure that your project is selected, and all folder under there are also! Good luck!
FatJar can help you in this case.
In addition to the"Export as Jar" function which is included to Eclipse the Plug-In bundles all dependent JARs together into one executable jar.
The Plug-In adds the Entry "Build Fat Jar" to the Context-Menu of Java-projects
This is useful if your final exported jar includes other external jars.
If you have Ganymede, the Export Jar dialog is enough to export your resources from your project.
After Ganymede, you have:
One more option is WinRun4J. There is an Eclipse Plugin for WinRun4J that allows you to export your application as a single executable with necessary jars/classes embedded.
(full disclosure: I work on this project)