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Problems with Ant build.xml configuration to work with external Libraries and Java property files

I have a problem with Ant Build Tool.
First, below you can see my project structure:
and the content of my build.xml file is:
<?xml version="1.0" encoding="UTF-8"?>
<project name="addonGenerator" default="main" basedir=".">
<property name="projectName" value="addonGenerator"/>
<property name="src.dir" location="src"/>
<property name="build.dir" location="bin"/>
<property name="dist.dir" location="dist"/>
<target name="compile" description="compile the source ">
<mkdir dir="${build.dir}"/>
<javac srcdir="${src.dir}" destdir="${build.dir}">
<classpath>
<pathelement path="lib/velocity-1.7.jar"/>
<pathelement path="lib/log4j-1.2.16.jar"/>
</classpath>
</javac>
</target>
<target name="dist" description="package, output to JAR">
<mkdir dir="${dist.dir}"/>
<jar jarfile="${dist.dir}/${projectName}.jar" basedir="${build.dir}">
<zipgroupfileset dir="lib" includes="velocity-1.7.jar" />
<zipgroupfileset dir="lib" includes="log4j-1.2.16.jar" />
<manifest>
<attribute name="${projectName}" value="main"/>
<attribute name="Main-Class" value="main.java.AddonGenerator"/>
</manifest>
</jar>
</target>
<target name="clean" description="clean up">
<delete dir="${build.dir}"/>
<delete dir="${dist.dir}"/>
</target>
<target name="main" depends="clean, compile, dist"/>
</project>
I don't know how setup the Ant build.xml to build and run my project with external libraries and the java property file generator.properties

To include your generator.properties file in the .jar file, add your resources directory when building the .jar:
<jar jarfile="${dist.dir}/${projectName}.jar" basedir="${build.dir}">
<fileset dir="src/main/java/resources"/>
Since you are currently building a “fat jar” (by directly including the contents of your library .jars in your application .jar), you can run by simply invoking your .jar file. Such a target obviously requires the .jar file to be built, so it makes sense to depend on the "dist" target:
<target name="run" depends="dist">
<java jar="${dist.dir}/${projectName}.jar"/>
</target>
On another note, I don’t think you want to pass src as your source directory, unless your classes actually declare themselves with ‘package main.java;’ (which they shouldn’t). You should pass the actual root of your packages to the javac task:
<property name="src.dir" location="src/main/java"/>
You should also make the "dist" target depend on "compile", since, well, it depends on having compiled classes available.
I also would suggest that your default target, "main", avoid calling the "clean" target. You should not clean before every single build; that defeats one of the most useful benefits of Ant, namely the ability to update only the things that need to be updated. You should only clean when you need to, with a command like ant clean compile or simply ant clean.
Note that once "dist" depends on "compile", and once "main" no longer calls "clean", you can simply remove the "main" target and change your project’s default target to "dist". When you think about it, this makes sense: the default action is to build and package the application.

Ant jar task include a single class file only

i have an ant task
<target name="create_jar" depends="compile">
<jar destfile="build/temp/MyClassJar.jar" basedir="build/classes/com/company/utils">
<manifest>
<attribute name="Main-Class" value="com.company.utils.MyClass"/>
</manifest>
</jar>
</target>
the folder build/classes has multiple packages and class files but in my jar i only want to include only two files MyClass.class and MyClass$1.class which are in com/company/utils folder.
if i have base-dir as com/company/utils when i run the task the jar does not have the package folders in like com/company/utils is not created inside the jar file but if i change my base-dir to build/classes then all the files are getting included.
what do to fix this.

The Jar task takes a nested fileset, so you can do this:
<jar destfile="build/temp/MyClassJar.jar">
<fileset dir="build/classes" includes="**/MyClass*.class" />
<manifest>
<attribute name="Main-Class" value="com.company.utils.MyClass"/>
</manifest>
</jar>

Ant include external .jar

I want to include external jar to my java project. I'm using ant. External .jar is in folder lib. My build.xml looks something like that:
<?xml version="1.0" encoding="UTF-8"?>
<project>
<path id="classpath">
<fileset dir="lib" includes="**/*.jar"/>
</path>
<target name="clean">
<delete dir="build"/>
</target>
<target name="compile">
<mkdir dir="build"/>
<javac srcdir="src" destdir="build" classpathref="classpath" />
</target>
<target name="jar">
<mkdir dir="trash"/>
<jar destfile="trash/test.jar" basedir="build">
<zipgroupfileset dir="lib" includes="**/*.jar"/>
<manifest>
<attribute name="Main-Class" value="com.Test"/>
</manifest>
</jar>
</target>
<target name="run">
<java jar="trash/test.jar" fork="true"/>
</target>
</project>
But it doesn't work. When I want to import something from the external .jar, there is an error after command ant compile: package com.something does not exist.. What should I edit to get it working?
Exact error:
Compiling 23 source files to xy/build
xy/src/com/Test.java:5: package com.thoughtworks.xstream does not exist
import com.thoughtworks.xstream.*;
^
1 error

You should try without the includes attribute:
<fileset dir="lib" />
And in the jar part you include the classes like this:
<zipgroupfileset includes="*.jar" dir="lib"/>

You can't put external libraries into a jar and expect the classloader to use those jars. Unfortunately this is not supported.
There are ant tasks like one jar that help you, to create a jar file, that contains everything you need.
This bit is from the background information of one jar:
Unfortunately this is does not work. The Java Launcher$AppClassLoader
does not know how to load classes from a Jar inside a Jar with this
kind of Class-Path. Trying to use
jar:file:jarname.jar!/commons-logging.jar also leads down a dead-end.
This approach will only work if you install (i.e. scatter) the
supporting Jar files into the directory where the jarname.jar file is
installed.
Another approach is to unpack all dependent Jar files and repack them
inside the jarname.jar file. This approach tends to be fragile and
slow, and can suffer from duplicate resource issues.
Other Alternative:
jarjar: Jar Jar Links is a utility that makes it easy to repackage Java libraries and embed them into your own distribution

I also use ant to include a number of dependency JARs in my JAR. My compile task looks like this. Perhaps something similar will work for you.
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}" includeantruntime="false">
<classpath>
<pathelement path="${classpath}" />
<fileset dir="${deps}">
<include name="**/*.jar"/>
</fileset>
</classpath>
</javac>
<copy todir="${build}">
<fileset dir="${src}" excludes="**/*.java"/>
</copy>
</target>

sometimes u can use jar contents directly, just unzip
<unzip src="/Developer-Java/mysql-connector-java/mysql-connector-java-5.1.22-bin.jar" dest="${build_dir}" />

NoClassDefFound error for a jar created using ant build

I have a java project with class having main method in package com.nik.mypackage. Only one library is referenced which is someLib-5.0.2.jar
This library is in lib folder in eclipse and added to the build path.
I am creating executable jar of the application using the below ant script target:
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="dist" location="dist"/>
<target name="init">
<tstamp/>
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init"
description="compile the source " >
<javac srcdir="${src}" destdir="${build}">
<classpath>
<pathelement path="${classpath}"/>
<pathelement location="lib/someLib-5.0.2.jar"/>
</classpath>
</javac>
</target>
<target name="dist" depends="compile" description="generate the distribution" >
<!-- Create the distribution directory -->
<mkdir dir="${dist}/lib"/>
<copy todir="${build}/lib" verbose="true" file="lib/someLib-5.0.2.jar" />
<!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
<jar jarfile="${dist}/lib/myProject-${DSTAMP}.jar" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="com.nik.mypackage.MainClass"/>
<attribute name="Class-Path" value="../lib/someLib.jar"/>
</manifest>
</jar>
</target>
The jar MyProject-20111126.jar is getting created. However, running the below command:
c:>java -jar MyProject-20111126.jar
is throwing a NoClassDefFoundError for a class in someLib.jar
What am I doing wrong ??
Thanks for reading!

When you run where is someLib.jar relative to the MyProject-20111126.jar?
The classpath you are setting up in the MyProject.jar is telling the VM to look for a lib folder in the parent directory of MyProject.jar.
The ClassPath entry in the manifest is interpreted relative to the location of the JAR file. It is used to locate jar files on the File System. The regular class loader in JAVA does not support JAR files bundled inside of JAR files.

As mentioned in the comment by Eric Rosenberg, we can not nest jar files inside other jar files. So we need to deflat the library and bundle individual classes in the app jar.

'Could not find the main class error' in a build file

I have craated a Java application with an Ant build file containing the jar-task task that generate a jar file from the application.
<target name="jar-task" depends="compile">
<mkdir dir="${jar.dir}"/>
<jar destfile="jar/guix.jar" basedir="${bin.dir}">
<fileset dir="${basedir}">
<include name="${basedir}/images/**/" />
</fileset>
<manifest>
<attribute name="Main-Class" value="IO.Deep.clk.GUI"/>
<attribute name="Class-Path" value="${basedir}/SPLASH-2.0.0.jar ${basedir}/lib/dist/* ${basedir}/user.properties"/>
</manifest>
<filelist dir="${basedir}" files="user.properties"/>
</jar>
</target>
When I execute on the command line however a NoClassDefFoundError stating
Could not find the main class IO.Deep.clk.GUI. Program will exit.
Now, the GUI file is exactly in the specific folder and in the same package, I really can't understand where the error may be...can anyone help?

The name images suggests, that the jar file will contain only images. But where is the actual code?
<fileset dir="${basedir}">
<include name="${basedir}/images/**/" />
</fileset>
This piece
<attribute name="Class-Path" value="${basedir}/SPLASH-2.0.0.jar ${basedir}/lib/dist/* ${basedir}/user.properties"/>
will write full qualified pathnames into the manifest. Are sure, that this is correct? Also note, that the code will not find user.properties by putting the file on the classpath. The classpath can contain only directories or jar-files in which classes or other stuff will be searched for. But simple files won't work.
I'm also not sure about the lib/* part. Is the class IO.Deep.clk.GUI in one of the jar files in that directory? That would be a hint, that all directories must be listed explicitly. If that's not a problem - good.
EDIT:
The classpath problems can be avoided by adding the task manifestclasspath (Ant docs) before the call of jar and by using the generated classpath value inside the manifest attribute. Outline:
<manifestclasspath property="jar.class.path" jarfile="jar/guix.jar">
<classpath>
<fileset dir="." includes="*.jar" />
<fileset dir="." includes="lib/*.jar" />
</classpath>
</manifestclasspath>
<echo message="Class-Path will be: ${jar.class.path}" />
<jar ....>
....
<attribute name="Class-Path" value="${jar.class.path}" />

Are you sure your resulting filest inside the jar task contains all the files you need?
For debugging you can use a path convert to the fileset out of the jar task and echo it so that you can verfiy that you have the correct files. If this is OK then I don't see something else wrong in your file although I have limited experience with the jar task myself.