Sounds like you are trying to install the 32-bit SQL Dev. The 64-bit comes with its own JDK, and should present no installation problems.
I cannot do upgrade to JDK 8 because I have another aplications those are not homologated to JDK 8.
Baloney! Who told you that?
I have 4 different Java versions of my machine and they don't interfere with each other at all.
You can have multiple versions on the same machine - whoever told you that is just wrong.