Why I cannot run code NullPointerException

Normally, In y code ardiuno is sent “SERIAL:ID15,ok,0:0:0,0.000000,0.000000,12.80,2134.87,-6754.32,0.00,0.00,0.00” to serial monitor
and in my code Arduino when i press ‘B’ it will sent hex data from JPEG CAMERA MODULE to serial port like"FF D8 FF E0 00 10 4A 46 49 46 00 01 01 01 …(more)…" so in my Processing I have to split for use Savebyte(); to image when i press’B’ i want to receive camera data and SaveByte(); to image and when it save already i want to go back to show "“SERIAL:ID15,ok,0:0:0,0.000000,0.000000,12.80,2134.87,-6754.32,0.00,0.00,0.00” like before.