title: Appending files to a zip file with Java
body: <p>I am currently extracting the contents of a war file and then adding some new files to the directory structure and then creating a new war file.</p>
  
  <p>This is all done programatically from Java - but I am wondering if it wouldn't be more efficient to copy the war file and then just append the files - then I wouldn't have to wait so long as the war expands and then has to be compressed again.</p>
  
  <p>I can't seem to find a way to do this in the documentation though or any online examples.</p>
  
  <p>Anyone can give some tips or pointers?</p>
  
  <p>UPDATE:</p>
  
  <p>TrueZip as mentioned in one of the answers seems to be a very good java library to append to a zip file (despite other answers that say it is not possible to do this).</p>
  
  <p>Anyone have experience or feedback on TrueZip or can recommend other similar libaries?</p>