scriptlla concurrency issues? - parallel-processing

Question

I use "antcall" scriptlla concurrent invocations, but appear "javax.mail. Management InstanceNotFoundException".
I set up 10 concurrent, sometimes can be 10, sometimes only a few can rise.
<target name="PAIR_CONN">
<etl debug="true">
<fileset file="Pair_Conn.xml" />
</etl>
</target>
<target name="pair_conn_mult">
<parallel threadCount='5'>
<antcall target="PAIR_CONN">
<param name="g_flag" value="1" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="2" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="3" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="4" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="0" />
</antcall>
</parallel>
</target>
Unable to unregister mbean scriptella:type=etl,url="file:/informatica/infa861/oss_etl_523/src/ElectricCable/Pair_Conn.xml"
javax.management.InstanceNotFoundException: scriptella:type=etl,url="file:/informatica/infa861/oss_etl_523/src/ElectricCable/Pair_Conn.xml"
I view scriptella source code, the code is already synchronized,
public synchronized void register() {
if (name != null) {
throw new IllegalStateException("MBean already registered");
}
server = getMBeanServer();
String url = ctx.getScriptFileURL().toString();
System.out.println("LM:"+url);
boolean registered = false;
for (int i = 0; i < 1000; i++) {
if (name == null || server.isRegistered(name)) {
registered = true;
name = toObjectName(url, i);
System.out.println("LM:"+name);
} else {
registered = false;
break;
}
}
etlThread = Thread.currentThread();
if (!registered) {
try {
server.registerMBean(this, name);
started = new Date();
LOG.info("Registered JMX mbean: " + name);
} catch (Exception e) {
throw new SystemException("Unable to register mbean " + name, e);
}
} else {
throw new SystemException("Unable to register mbean for url " + url + ": too many equal tasks already registered");
}
}
What suggestions to you have for this situation ? What should I try, or what should I read in order to find a solution ?

Answer 1

Thanks for pointing out a serious bug. I've opened JavaForge ticket to track this issue.
As a workaround you can switch to <java fork="true"> task to run Scriptella in a forked VM, so the Ant script will become something like this:
<path id="scriptella.class.path">
<pathelement location="../../build/scriptella.jar"/>
</path>
<taskdef resource="antscriptella.properties" classpathref="scriptella.class.path"/>
<target name="PAIR_CONN">
<java fork="yes" classname="scriptella.tools.launcher.EtlLauncher" classpathref="scriptella.class.path">
<arg value="Pair_Conn.xml"/>
<arg value="-d"/>
<sysproperty key="g_flag" value="${g_flag}"/>
</java>
</target>
<target name="pair_conn_mult">
<parallel threadCount='5'>
<antcall target="PAIR_CONN">
<param name="g_flag" value="1" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="2" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="3" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="4" />
</antcall>
<antcall target="PAIR_CONN">
<param name="g_flag" value="0" />
</antcall>
</parallel>
</target>