Java 5 or 1.5? the plot thickens

I have managed to sucessfully download the J2SDK 1.5 (or is it jdk 5.0 ?) at last. (Previous attempts resulted in a corrupted file). The file that I have in my hands is labeled jdk-1_5_0-beta2-linux-i586.bin so I am not sure why the installation instructions at

http://java.sun.com/j2se/1.5.0/install-linux.html

should refer to java 5.

Update March 23, 2023 : those links to sun.com are no longer valid of course