Hi
I am trying to make an java application to compress file and folders in .zip format..
i want to add additional functionality of adding password to a zip file,for this i want to use aes-256 algorithm but i am stuck with this,i can't figure it out.
if i apply aes algorithm to file and add password where this password get stored??in the file crc or in some file data field,
Do i need to use an API for this or else this could be done without api and by creating my own java program??

There exists a project similar to what you are looking for on google code. You could look at the source code how they did it even though you do not want to use their codes.