Possibly related past discussions:
- Share Sketch in Local Network - Processing 2.x and 3.x Forum
- Full screen Syphon / NDI Processing Q's - #2 by mattleaf - VIDVOX
I’m not sure what this means? Do you mean that you are running parallel syphons, or that you are pushing too many pixels and have bandwidth / RAM problems?
If you want Java bindings for the Newtek NDI SDK perhaps check out Devolay. A new release came out just a few days ago.