title: Create one Zip file using a set of pdf files
body: <p>My app is a tender document system where each tender number has one or more pdf files attached.</p>
  
  <p>application is done in java ee using struts and mysql.</p>
  
  <p>in a database table the paths of each related pdf file for a tender number is stores.</p>
  
  <p>I want to get all the pdf files and create a single ZIP file for each tender number so that user can download that zip file and have all the related documents in a single click.</p>
  
  <p>I tried Google and found something called <code>ZipOutputStream</code> but i cannot understand how to use this in my application.</p>