DevOps, CI/CD and Automation

Hi,
iam generating a pdf file by calling the report server as follows
Process subProcess = runTime.exec( "rwclient report=" +
argsForReport[ 0 ] + " server=" + argsForReport[ 1 ] + " userid=" +
argsForReport[ 2 ] + " destype=file desformat=pdf PROJECTNUMBER=" +
projectNumber + " USER_ID="+userId.intValue()+" desname=" + url + "" );

this is generating the pdf file.
But i have a requirement that i have to call this in a loop so that all the pdf file generated should come into only one pdf file.
Is this possible ?
Any any one help out sloving this problem

thanks and regards
kalyan