Groupon is the daily deal websites that serves many major international markets, offering one coupon per day in each these markets. You can’t go anywhere online these days without spotting a Groupon ad. It's theory as we all know - the social features of its deep-discount offers for local merchants — a certain size group had to sign up in order for the deal to be “on” has been the reason for the huge success.
Java is a general-purpose, concurrent, class-based, object-oriented computer programming language that is specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another.
Commercial software, or less commonly, payware, is computer software that is produced for sale or that serves commercial purposes, a customer of the proprietary software pays a fee for a license to use the software.