<target name="datanucleusenhance" depends="compile"
    description="Performs enhancement on compiled data classes.">
    <enhance_war war="war">
    </enhance_war>
</target>

<target name="datanucleusenhance" depends="compile" description="Performs enhancement on compiled data classes.">
    <enhance_war war="war">
        <args>
            <arg value="-enhancerVersion" />
            <arg value="v3.1.0" />
        </args>
    </enhance_war>
</target>

java.lang.RuntimeException: Unexpected exception
    at com.google.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:76)
    at com.google.appengine.tools.enhancer.Enhance.<init>(Enhance.java:71)
    at com.google.appengine.tools.enhancer.Enhance.main(Enhance.java:51)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:74)
    ... 2 more
Caused by: java.lang.NoClassDefFoundError: org/datanucleus/OMFContext
    at org.datanucleus.enhancer.DataNucleusEnhancer.<init>(DataNucleusEnhancer.java:172)
    at org.datanucleus.enhancer.DataNucleusEnhancer.<init>(DataNucleusEnhancer.java:150)
    at org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:1157)
    ... 7 more
Caused by: java.lang.ClassNotFoundException: org.datanucleus.OMFContext
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at com.google.appengine.tools.enhancer.EnhancerLoader.loadClass(EnhancerLoader.java:107)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    ... 10 more

<target name="datanucleusenhance" depends="compile" description="Performs enhancement on compiled data classes.">
    <enhance_war war="war">
        <args>
            <arg value="-enhancerVersion" />
            <arg value="v2" />
        </args>
    </enhance_war>
</target>