Fork process exception: enclosed small code and exception

Question

A code snapshot is enclosed along with the exception we are getting on our production system.
My class file namely as StatementProcessParametersAction.saveParameters() method does following as enclosed the code snippet.
CODE ------
     String val =   (String) request.getParameter("x");
     String jobId = request.getParameter("jobid");
     if ("1234".equals(val)) {
       try {
          Runtime.getRuntime().exec("java -classpath /export/bea/Mah-ARCS/ARCSDomain/cron ups.arcs.batch.ArcsBatchExecutioner http://arcsreport.inside.ups.com/ArcsContent/arcsinterfaceservlet processType statements command  " + jobId);
       catch (Exception e) {
           e.printStackTrace();
     }EXCEPTION ----
ERROR 20 Mar 2006 09:04:53,569 StatementProcessParametersAction.saveParameters(): an unexpected error has occurred. Details: java.lang.UNIXProcess.forkAndExec(Native Method)
java.lang.UNIXProcess.<init>(UNIXProcess.java:52)java.lang.Runtime.execInternal(Native Method)
java.lang.Runtime.exec(Runtime.java:566)java.lang.Runtime.exec(Runtime.java:428)
java.lang.Runtime.exec(Runtime.java:364)java.lang.Runtime.exec(Runtime.java:326)
myapp.arcs.app.action.StatementProcessParametersAction.saveParameters(StatementProcessParametersAction.java:562)
myapp.arcs.app.action.ArcsBaseParametersAction.submitParameters(ArcsBaseParametersAction.java:394)sun.reflect.GeneratedMethodAccessor967.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:324)
org.grnds.structural.struts.icl.IclLookupDispatchAction.dispatchMethod(IclLookupDispatchAction.java:311)
org.grnds.structural.struts.icl.IclLookupDispatchAction.execute(IclLookupDispatchAction.java:237)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(ServletStubImpl.java:996)weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:419)w
weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:28)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:27)
myapp.arcs.filter.GZIPFilter.doFilter(GZIPFilter.java:38)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:27)
weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:6458)
weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
weblogic.security.service.SecurityManager.runAs(SecurityManager.java:118)
weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3661)
weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2630)
weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:219)
weblogic.kernel.ExecuteThread.run(ExecuteThread.java:178)---------------------
I have done lot of googling on this UNIXProcess.forkAndExec and found out that it is related to our SUN UNIX version 8.0 SWAP space problem. I did one test to reduce the SWAP space to 2 gig from 6 gig and recreated the problem ourself in Testnet.
Now, i was looking for some answers ....
1) I do not like forking a process (as it is like creating a new JVM within an already existing JVM) and do stuff from there. Now, what is the best way to implement these forking scenerios within the same JVM (here BEA Weblogic) and NOT forking a new JVM.
2) Just curiuos --- why does the Unix fork processes uses SWAP space rather than the real memory lying on the Unix box.
I may be asking this question very awkwardly but this is the best way to write my question from my mind. Iam really confused about all this forking and stuff. So, please ignore me if the answer is asked half baked.
Thanks,

Answer 1

also to add to my queries ....
in our code, we are catching exception like this ....
    catch ( Exception e )
      logger.error( TRACE_TAG + methodName + GENERIC_ERROR +
                    CommonUtils.getStackOutput( e ) );
}Now, the exception that iam getting is a Runtime exception (correct me if iam wrong though) ...
My question is (to learn about exception....:))
isn't Exception is a very high level Exception handling .... does the code need to catch a more specific exception handling like "RuntimeException"