Open processing, go to tools and install "processing-java"

download this https://github.com/sophacles/vim-processing and put the syntax folder into ~/.vim (or the file processing.vim into your syntax folder if you already have one

add these two lines to your vimrc, the first of which sets up syntax highlighting and the second allows you to run and compile from vim:

au BufRead,BufNewFile *.pde     setf processing
:command P :! processing-java --sketch=$PWD/ --output=temp --run --force

:P from vim compiles and runs a sketch

If you want to use a different editor, you can run from the command line with the command processing-java --sketch=$PWD/ --output=temp --run --force