To install a version in your mac you can run the command sdk install java 15.0.0.j9-adpt. Replace 1.7 and 1.8 with whatever versions you are interested with and you'll get an alias called 'javaX'; where 'X' is the java version (7 / 8 in the snippet below) that will allow you to easily switch versions.
I bought a new Macbook recently which run Catalina (OS X 10.15) which is basically no different to OS X 10.11 or 10.10 – the only difference is that it slows your computer down if you are on an older model. Since Steve Jobs died innovation at Apple basically stopped; all the new devices is just the same as before but maybe with an extra camera or a bit more RAM or a faster CPU. The laptop that I bought is no exception compared to the Macbook Air that I bought 8 years ago.
I use Adobe Photoshop CS6 which requires Java 6 SE; it’s supposed to be an older version of JAVA but it actually does the job; but the JAVA downgrade that Apple offers doesn’t work for Catalina (10.15) – https://support.apple.com/kb/DL1572?viewlocale=en_US&locale=en_US; it should but they just deliberately made it so it doesn’t.
Mac OS X Yosemite (and the newer versions) are having a later version of Java Runtime (SE 8.0). However, Java Runtime is not backward compatible. So, even when the operating system have installed Java Runtime 8, it will NOT run apps that rely on Java Runtime 6. Apple's Java 6 is no longer supported on Catalina, so the Java for macOS 2017-001 installer is toast too. Replace the old 32-bit Java 6 dependent applications with Catalina compatible applications, or use them on older releases of macOS than Catalina. Installing Java OpenJDK on macOS Catalina Posted on September 28, 2018 by Paul. Updated 15 October 2019. This is a short note about getting started with Java 11 LTS or Java 13 on macOS Catalina. As you probably know, starting with Java 11 there was a big change in the license under which the official Oracle JDK is provided.
I found a great post online on how to fix this:-
https://www.harrisgeospatial.com/Support/Self-Help-Tools/Help-Articles/Help-Articles-Detail/ArtMID/10220/ArticleID/23780/Mac-OS-Catalina-1015-ENVIIDL-and-Legacy-Java-6-Dependencies – It really works and I was surprised.
The error message that you will receive is “A Newer Version of this package is already installed” but it’s not.
I followed the instructions on the Harris Geo Spatial website and managed to generate a package that I was able to use to install JAVA6 SE; to save people hassle I have uploaded here and you can download it directly to save yourself from following the steps yourself. You download:-ModifiedJava6Install.pkg
Java 6 Mac Os Catalina Free
I also download JAVA 7 too which can be downloaded here – it needs X86_64 architecture:-
jdk-7u80-macosx-x64.dmg