Here is the solution I came up with at the end. It uses Ant and generates javadoc and source jar. Then it archives binary jar, javadoc, source.jar, licence and readme file in to a zip file that is ready to release.
<target name="-pre-init">
<property file="version.properties"/>
<property name="dist.jar" value="dist/${ant.project.name}-${project.version}.jar"/>
</target>
<target description="bundle sources in a jar" name="package-sources">
<jar basedir="src" destfile="build/release/${ant.project.name}-${project.version}-sources.jar"/>
</target>
<target name="package_for_release" depends="jar,javadoc, package-sources">
<mkdir dir="build/release"/>
<copy file="${dist.jar}" todir="build/release/"/>
<copy file="licence.txt" todir="build/release/"/>
<copy file="beni_oku.txt" todir="build/release/"/>
<mkdir dir="build/release/doc"/>
<copy todir="build/release/doc">
<fileset dir="dist/javadoc" includes="**"/>
</copy>
<zip basedir="build/release/" includes="**" destfile="dist/${ant.project.name}-${project.version}.zip"/>
</target>
Open build.xml in NetBeans than right click - > run target -> [other targets] -> package_for_release
Script gets the version number from a properties file. I got this solution from here.