Too Difficult to Install Older JDKs on Mac OS

This is sometimes needed for development work, i.e. to test on an older JVM. It is possible to tell Eclipse to e.g. compile according to Java 1.4 or Java 5 language rules, but since the rt.jar or equivalent file(s) are based on Java 6, if you were to use a class or method that only exists in Java 6 and above, Eclipse wouldn't flag the error.

There is no doubt that it is possible to compile e.g. Java 1.4 bytecode on Mac OS, but the inability for Eclipse to check for usage of classes that don't existing in a 1.4 JVM is a problem.

It is not known if it is possible to install a Java 1.4 JVM. There is enough evidence from online articles / posts that suggests that even if it's possible, it is difficult.

Reference: http://stackoverflow.com/questions/1577014/how-install-a-specific-jdk-on-mac-os-x