I have jrxml file, I want to compile this to get .jasper. How do I compile and get that jasper
For anyone coming across this question who uses Jaspersoft Studio (which, I think, is replacing iReports; it's quite similar, still freeware, just based on eclipse), look for the "Compile Report" icon on top of the editor area of your .jrxml file. Its icon, first in that line of icons, is a file with binary numbers on it (at least in version 5.6.2):

Clicking this icon will generate the .jasper file in the same directory as the .jrxml file.