I'm developing Swing based application in Java I want a executable JAR file for this project.
All external library files used in the project should be packaged in the JAR file.
How can I build a runnable JAR file using ANT?
but it needs all external library
files used in the project should be
along with the jar.
Of course, but the external JARS should not be bundled in with the executable JAR.
You need to do three things:
Create a manifest for your executable JAR that specifies the Main-Class.
Add the CLASSPATH to you manifest that spells out the location of each and every dependent JAR relative to the executable JAR.
Create a ZIP file that contains the executable JAR and all the dependent JARs, with paths relative to the executable JAR as specified in your manifest.
You give clients the ZIP. They unpack it and execute your executable JAR.
You need to include the manifest task in your jar task. The manifest references the main class to be executed by default when you start your jar.
it could look like this :
<jar...
<manifest file="MANIFEST.MF">
<attribute name="Main-Class" value="com.example.YourMainClass"/>
</manifest>
</jar>
Related
Below is my Jar structure. This is standalone jar.
MyApp.jar
--> .settings
--> com
--> lib
--> META-INF
--> resources
--> .classpath
--> .project
I am attempting to execute this jar file from bat file.
I have mentioned classpath and main class in MANIFEST.MF file under META-INF folder from MyApp.jar
Manifest-Version: 1.0
Class-Path: ./lib/jar1.jar ./lib/jar2.jar ./lib/jar3.jar
Main-Class: com.bank.Main
Inside my bat file:
java -jar D:\app\MyApp.jar
Is it correct way to lib folder inside jar?
But still i am facing ClassNotFoundException.
Exception in thread "main" java.lang.NoClassDefFoundError: javax/jms/JMSException
Anything i missed out Please advise me.
Put the lib folder outside of your current main jar [MyApp.jar] directory and execute it.
You have packaged the jar dependency inside your main jar. The intention of Class-Path is to add an external jar to the classpath, with the path relative to the location of the main jar.
Packaging a jar within a jar is not supported by standard Java classloaders. If you want, you can explode the inner jar into the main jar, though. Maven can do this for you.
Fat jar is not supported in Java by default. There are two options.
You can define a custom class loader which has to load jars inside lib directory programmatically.
You can manually merge all packages of jars inside lib directory to make a one jar and run it. Refer [https://dzone.com/articles/java-8-how-to-create-executable-fatjar-without-ide ]
The structure of my first app is simple:
libs
opencsv-3.8.jar
yamlbeans-1.0.jar
out
artifacts
...
production
...
src
META-INF
MANIFEST.MF
pl.krzysiu
App.java
CsvReplacer.java
Everything is fine during the compile and running the program. After building artifact jar file in the default out\artifacts directory, I get
java.lang.NoClassDefFoundError: net/sourceforge/yamlbeans/YamlException
when I try to run it by java -jar CsvReplacer.jar command
The libraries are included inside the jar file (they are there after unpacking it) - they are added to Libraries section in Project Structure (separately - one file per one lib), the whole libs dir is included in the Dependencies tab of Modules section (with export checkbox checked) and the libs dir is added in Output Layout of Artifacts section similarily.
The manifest file contains:
Manifest-Version: 1.0
Class-Path: libs\yamlbeans-1.0.jar libs\opencsv-3.8.jar
Main-Class: pl.krzysiu.App
Why the libs aren't visible for the App? If I copy this dir manually to the CsvReplacer.jar file's location - everything works fine.
The structure inside CsvReplacer.jar file looks like:
libs
opencsv-3.8.jar
yamlbeans-1.0.jar
META-INF
MANIFEST.MF
pl
krzysiu
App.java
CsvReplacer.java
IDE: Intellij IDEA 2016.3
The standard Java classloaders cannot find a JAR file embedded inside another JAR file.
You have two choices when making an executable JAR with dependencies.
Create a so-called uberJAR file by merging the contents of the dependent JARs into your main JAR.
References:
IntelliJ IDEA export Runnable program as Uber Jar
https://blog.jetbrains.com/idea/2010/08/quickly-create-jar-artifact/
Give your JAR a "Class-Path" manifest attribute to tell it where the (external!) dependent JARs are located.
You can't give a -cp and a -jar option together. But another alternative would be to get rid of the -jar option and use a -cp argument to specify the classpath.
Alternatively, you could implement a custom classloader that can load from a jar inside a jar, or use something like one-jar or Spring Boot.
I am using Java Simple Plugin Framework. I export a jar that has my plugin implementation. The implementation depends on a library, which I have as a jar. That jar gets exported within the lib directory of my jar, and added to the classpath of my jar.
But when I load my jar with JSPF, it fails with "NoClassDefFound" because it can't find the jar in the lib director of my jar.
My apologies if my approach off base; I just need to know how this is supposed to be done. How should I bundle my plugin implementation as a jar if it depends on another jar?
I used JSPF and achieved this requirement the following way:
place the library jar file in a folder called lib outside the plugin jar file. (So that
the lib folder and the plugin jar file is in the same folder). Then I added lib/"name_of_libjar" to the classpath entry in the manifest.mf file of the plugin jar file (Which should be inside the plugin jar files META-INF folder), and it worked fine for me.
I am using eclipse to create a runnable jar. During runtime my code looks through the classpath for a config file, which it reads in. However, as a runnable jar it is not finding this config file.
I guess the config file will need to exist as a seperate entity on the filesystem somewhere. How do I specify the classpath in the Manifest to include this location when eclipse creates the runnable jar?
Thanks
Ensure your config file is under an eclipse source folder:
I use
src\main
src\test
src\resources
All three are folders, added to the Eclipse project as source folders
If I add three files (one.xml, one.properties and one.config) to the src/main/package/ folder and then export a runnable jar they all appear in the runnable jar.
I have a project that uses the serial port, and it requires two files to run, the win32.dll file (which is in the java runtime environment bin folder) and the javax.comm.properties file (which is in the java runtime environment lib folder). When I run the project from eclipse it works, but when I try to build a jar file for distribution, it won't work. I suspect this is because the dll and properties files aren't included in the jar. How do I specify that they need to be there?
You generally don't put dll and properties files inside the jar. Properties files as well other jar files need to be added to the classpath. The jar file has a manifest file that defines the classpath used. You can't edit this with eclipse. You need to define an ant build.xml file and do something like this:
<jar jarfile="${dist}/MyJar.jar" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="MyClass"/>
<attribute name="Class-Path" value="."/>
</manifest>
</jar>
Then put the properties file in the same folder as the jar. You can run the ant target by right clicking the build.xml and selecting the "Run as Ant target".
If I remember correctly, placing the dll file in the bin directory of the jre will work.
I think javax.comm.properties just need to be on your classpath. You may can add it to the top level of a jar you delivery.
InputStream is = MainClass.class.getResourceAsStream("javax.comm.properties");
if (is == null) {properties missing....}
I think win32.dll just need to be on the %PATH%(windows) or $LD_LIBRARY_PATH(unix)......
A jar file is just a normal zip file. If you want to add files to it, just use a tool such as winzip.
With Ant, you can pack everything in your Jar you want to. So let Ant create your Jar, not Eclipse :)