When and Why run alternatives --install java jar javac javaws on installing jdk in linux

Question

To install java in linux (I used CentOS, RHEL is same too), I used this command

rpm -Uvh /path/to/binary/jdk-7u55-linux-x64.rpm

and verified java

Answer 1

These "alternatives" scripts and similar tools just symlink binaries of desired JDK version to the directories they are expected to be. It's done for all commands that should be available on your command line.

Definition of "all" depends on your distro.