What you have downloaded is NOT the version for linux. Browse through the site and down load the required jsdk for linux. They probably have an rpm for RedHat which you can use.
rpm -i filename
to install the file.Then you will have it installed. As for runnning servlets, you probably have to download tomcat server and set it up. It has instructions about setting it up, and if you have any doubts post it and I will help you.
About installing tar files, search through the site as already too many newbies have asked this question, and if you have any specific doubt post here.