There is a public JRE component inside JDK installer, I did the following test on one machine:

1. Install JRE 6u5 on that machine.
2. Install JDK 6u10 on the same machine, the public JRE component didn't show up during installation, it is thinking the machine already has the latest JRE 6u10, which isn't correct.

I tested on both 32bit and 64bit OS, with 32bit JDK and 64bit JDK, the same issue has been found. It is important to fix this issue in 64bit OS because it will stop to install 64bit JRE when you have a 32bit 6u5 JRE installed on user's machine.
Posted Date : 2008-05-05 19:44:01.0

N/A

This is correct behavior.

As of 6u10, our stance is that if they already have a public JRE of the same family (6), then we do not offer a public JRE.  It was getting to be too much of a headache to deal with all of the reinstall behavior in those cases, and with little reward.  We depend on auto-update to keep their public JRE up-to-date. 

If the true 64-bit installer is asking for a reinstall of the public JRE, then that's the bug.
Posted Date : 2008-05-16 16:59:28.0

this has nothing to do with 64 bit install.
install of JDK is not offering JRE install
Posted Date : 2008-06-05 19:28:49.0

The fix would involve changing the Condition.idt table for the sdk, as well as the RegLocator for NewSignature2.

Something like this:

<<NewSignature2   2       SOFTWARE\JavaSoft\Java Runtime Environment\[MAJOR].[MINO
R]      JavaHome        2^M
>>NewSignature2   2       SOFTWARE\JavaSoft\Java Runtime Environment\[FULLVERSION]      JavaHome        2^M
Posted Date : 2008-06-06 18:59:59.0