I have one file created by 7zip program. I used **deflate** method to compress it. Now I want to create the same archive (with the same MD5sum) in `java`. When I create zip file, I used the algorithm that I found on the Internet for example <http://www.kodejava.org/examples/119.html> but when I created zip file with this method the compressed size is higher than size of the uncompressed file so what is going on? This isn't a very useful compression. So how I can create zip file that is exactly same as zip file that I created with 7zip program ? If it helps I have all information about zip file that I created in 7zip program.