Remove extra white space

When I print ticket always has a huge white space bottom of ticket. How can I remove this extra white space. please look at the attach file.

system can not upload the image file

1. Priter settings. 2. Custom ticket.

How can get printer settings? From admin app?

The settings of a printer or driver of the printer. Discover your device.

I checked my printer device it is not related to my printer. it is because of print code in FWelcome.java file. I think that it is because of default paper size. But I don't know how to change. From code or welcome.properties file
https://www.dropbox.com/s/4qtgl7g56q9p1xn/20160503_172502.jpg?dl=0

Look into config/welcome.properties

Where is param 'bottom_gap' for normal printing.

Your case is problem of printer exactly. Could be driver is weird as usual.
For this case you can use properties in welcome.properties from PRINTER area. It is challenge.

I solved the problem just change the below property in welcome.properties file default is 1.

printer.MediaSizeName.EXECUTIVE=0