Well, yes, unless you are in the OP's position, and want to use CS3 on a newer system, such as El Capitan or Sierra. You need Apple's installer for Java SE 6. Apple makes it available (and updates the installer as newer versions of macOS appear, I guess), as some apps still need that old Java version (and won't work with a newer Java version.)
Which would explain why the OP posted with the question.