I asked the question because even product makers are different kernel is nearly same for both.
So I thought that if Linux and Solaris are same then by learning Linux I will automatically upgrade to Solaris with some differences.
I am beginner in Linux and learning Linux to the some extent but also want to upgrade my knowledge about Solaris.
The kernel is only a tiny part of any operating system. Its all the rest of the stuff, X-windows, the shell tools (vi, grep, cat, etc.), along with windows managers, bundled utilities, etc. that make a distribution.
At a high enough level, all of the Unix/Linux versions look the same, but at a lower level, there are lots of changes.
If you asked about Fedora and RedHat, or Debain and Ubuntu, the answers would still be "they are different" but they have more in common than RHES and Solaris.
No even close. I used to joke that 2006 Solaris 8 was a lot like 1991 Linux. They're both "Unix" systems, so a lot of the commands are essentially the same - though the Linux ones often have extra features. But Solaris was designed to be a bit more like mainframes, so it has some heavy-duty resource management stuff (although I knew one shop that ignored it). With Solaris 10 was added a very powerful successor to the old-fashioned init script facility that's still very much use in Linux. Linux - especially RHEL - has evolved in its own directions and has its own strengths.
From a strictly user point of view, if you're familiar with one OS, you should be able to get by on the other, but you can't expect everything to function exactly the same or to find all the files in the same places. Of course that's also true between Ubuntu/Debian and RedHat/Fedora, but the differences are somewhat greater.
Customer surveys are for companies who didn't pay proper attention to begin with.