Wrapping an existing ant target so you can pass in a javaagent and other jvm args

If you have an ant task that requires a javaagent such as spring's instrument.jar,
you might get this stack error message.

Caused by: java.lang.IllegalStateException: ClassLoader [org.apache.tools.ant.loader.AntClassLoader5] does NOT provide an 'addTransformer(ClassFileTransformer)' method. Specify a custom LoadTimeWeaver or start your Java virtual machine with Spring's agent: -javaagent:org.springframework.instrument.jar



Solution is to wrap the offending ant target with the javaagent:org.springframework.instrument.jar




So:
if your build.xml   file has the following target,  

  <target name="create-sql">

       .... code that requires javaagent

    </target>

then you would add a new wrapper target, like so:

 <target name="build-create-sql" >

        <!--wrapping spring insturment jar-->

            <java  classname="org.apache.tools.ant.launch.Launcher"

                    fork="true"

                    failonerror="true"

                    dir="."

                    timeout="4000000"

                    taskname="startAnt">

                    <classpath>

                        <pathelement location="${ant.home}/lib/ant-launcher.jar"/>

                    </classpath>

                    <jvmarg value="-javaagent:${spring.instrument.path}"/>

                     <jvmarg value="-XX:MaxPermSize=512M" />

                    <jvmarg value="-Xmx1024M" />

                    <arg value="-buildfile"/>

                    <arg file="build.xml"/>

                    <arg value="create-sql"/>

              </java>

    </target>

Now you can pass in a spring instrument jar as a jvmarg and javaagent in your new ant target and the existing target does not have to be modified.