Exporting and distributing your work
One of the most significant features of the Processing environment is its ability to bundle your sketch into an applet or application with just one click. Select File → Export to package your current sketch as an applet. This will create a folder named applet inside your sketch folder. Opening the index.html file inside that folder will open your sketch in a browser. The applet folder can be copied to a web site intact, and will be viewable by anyone who has Java installed on their system. Similarly, you can use File → Export Application to bundle your sketch as an application for Windows, Mac OS X, and Linux.
The applet and application folders are overwritten whenever you export—make a copy or remove them from the sketch folder before making changes to the index.html file or the contents of the folder.
More about the export features can be found in the reference here
~save your sketch
~export your sketch
~choose upload file on the blog
~select applet folder
~select file with the file extension .jar