Develop Reference

java.lang.NoClassDefFoundError after building jar file in Intellij

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.

How Do I add dependency for Java?

I'm very new to Java. I have a single class file which is used to do some processing.
That class file is depended on a jar. I'm very new to Java, where I'm passing the jar to my classpath while running the program:
javac -classpath jar MyProgram.java
Now I wish to bundle both the jar and MyProgram into separate jar with dependency resolved.
Are there any ways to do this in Java? Note that it my MyProgram java is only around 50 lines of code, so some simple solution will be good.
Thanks in advance.

You cannot put the library JAR inside another JAR file - Java will not be able to load classes from embedded JAR files.
You could create a JAR file containing just the classes of your application, and have the library JAR alongside it. See Packaging Programs in JAR Files for details on how to do this exactly.
If you really want everything to be in a single JAR file, you could use a tool such as One-JAR to package it.

You should not bundle both your compiled code and the dependency in a separate jar. You should bundle only your compiled classes in a jar and when running the program, you put both your jar and the dependency in the classpath.
Use the jar command to build your jar file and then use the command below to run your program:
java -classpath dependecy.jar;yourjar.jar MyProgram

How to build a distributable jar with Ant for a java project having external jar dependencies

I have a Java project in Eclipse with class MainClass having main method in package :
com.nik.mypackage.
The project also references two external libraries, which I copied in the lib folder in Eclipse and then added to build path using ADD JAR function. The libraries being one.jar and two.jar
This library is in lib folder in eclipse and added to the build path.
I want to create a executable JAR of the application using ant script. So that user can access my application using command:
c:>java -jar MyProject-20111126.jar
I know about the Eclipse plugin which directly exports a java application as runnable JAR. But I want to learn ant and the build process so manually want to create the build.xm.

You have two options from your build.xml. You can either unjar the library jars and then bundle their contents with the code compiled for your application. Or, you can put the library jars on the filesystem and supply a ClassPath entry in the manifest file of the MyProject-2011126.jar file.
If you set the classpath in the manifest remember that the path you supply is relative to the MyProject-2011126.jar.

one alternative:
Instead of having only a jar, you build mutiple jars (your jar + libs) +batch file.
So, your built package can be like this structure:
-/package/bin/app.bat
/package/lib/my.jar
/package/lib/one.jar
/package/lib/two.jar
In app.bat you just have the same as your code
java -jar MyProject-20111126.jar
PS: if you want to start learning built tools, ANT may be a bit tool old. I suggest http://maven.apache.org/

Please try one-jar. It helps to redistribute everything packaged as single jar and comes with ant-task . See Easiest way to merge a release into one JAR file.

Using JAR inside a jar

I created a JAR file from my java project.
Using Eclipse, I added a JAR as a referenced library in my own project.
However, now when I try to run my program's JAR using java -jar myProgram.jar, I get an exception stating that my referenced jar is not available.
So how can I create a JAR consisting a reference to a different JAR and make it work?

Right, an executable JAR cannot contain its own JAR dependencies.
You have to have the main class and classpath set in the executable JAR manifest, then package all your JAR dependencies along with the executable JAR in a relative directory structure that matches the manifest CLASSPATH. Reading this might help.

You need to use Eclipse's runnable JAR exporter. Since Eclipse 3.5 you've the following options when you rightclick project, choose Export > Runnable JAR file:
Either way, Eclipse should take care that you'll be able to run the JAR the way you want on the exported location.

See jarjar project. It is exactly what you are looking for. http://code.google.com/p/jarjar/

creating jar file for java application

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