[Solved]-"testng doesn't support the nested "java" element."- while executing build.xml - JAR target-eclipse

<!-- runs the file and generates reportng report for testng-->
<taskdef resource="testngtasks" classpath="${dependencies}/testng-6.9.9.jar" />
<target name="testng-execution" depends="jarextraction">
    <testng testjar="${cashkarojar}" xmlpathinjar="local/${xmlfile}" classpathref="classpath" usedefaultlisteners="true">
        <sysproperty key="env.url_key" value="ck_auto_dev"></sysproperty> 
    </testng>
</target>

i believe that the problem is due to the inclusion of <java jar="${jar.dir}/${ws.project.name}.jar" fork="true"/> in your <target name="runs" depends="compile,jarcreation">

to fix this you need to remove the <java> element from the <testng> element and try again.

for more information on the available options, refer here