Contributing to MacInTouch recently spawned a slew of questions and answers regarding Apple, macOS, 32-bit apps, Adobe Creative Suite and Java including some incorrect information. So I decided to tidy everything up into a quick, simple breakdown answer including correcting those inaccuracies and posted a reply. As my reply was essentially a useful summary of all these software products, the reply became the basis for this blog post.
All 32-bit apps will stop working in macOS 10.15 "Thingymajig" from ~September 2019 - see macOS 32-Bit Applications To Be Unsupported In The Future article on MacStrategy. If you want to run 32-bit apps in macOS 10.15 or later you will need to virtualise an older version of macOS - see recommendations below.
Java (not to be confused with JavaScript), and to keep it simple for people to understand, can be considered as a virtual operating system environment running on top of macOS - this is also known as the Runtime Environment which is why you see the term Java RE. There are different versions such as the Standard Edition (SE) and the developer edition (Java Development Kit - JDK). Java was included with macOS up until Mac OS X 10.6, then it became a separate installation - either Java RE 6 (which Apple produced) and/or Java RE 7 and later (which Oracle produces).
I have more information about Java on MacStrategy. As Java is essentially a virtual operating system environment running on top of macOS it's a potentially major security weakness - if you install Java keep it up-to-date.
David Zatz incorrectly stated on MacInTouch that the Creative Suite installers require Java. This is not true. Installing CS3-CS6 does not require Java. I know this because I extensively tested all the CS versions on many OSes during 2015-2017. However, once installed, running/launching certain CS apps ask for Java but they don't in fact require Java - it's nothing to do with the Help system as Paul Chernoff speculated on MacInTouch. You can read all about my testing and which CS apps request/require Java in my Adobe Creative Suite CS and Java RE v6 article on MacStrategy.
David Zatz on MacInTouch linked back to the CS installer problems on later macOS versions - the reason for this is not Java but because Adobe are a$$holes and created a proprietary installer that spews crap all over your hard drive. This older installer has not been updated to work properly with later versions of macOS because, hey, Adobe could update it if they wanted to, but they'd rather you succumb to the Adobe Creative Cloud subscription instead.
George stated on MacInTouch that " The problem with Java was that most web browsers included / offered a Java plugin". This is not true. Browsers on macOS don't come with the Java plug-in. Either the macOS itself includes the Java plug-in or you manually install Java and with it comes the plug-in.
Apple included the Java plug-in in the OS up until OS X 10.8 (I know this because I just checked it right now on my "All Mac OSes Clean Installations" partitioned test hard drive). OS X 10.9 and later requires a separate installation of Java (see above) to get the plug-in.
George then correctly states on MacInTouch that the Java plug-in is NPAPI based and support for NPAPI plug-ins has been removed in most browsers except Safari v11 and earlier so going forward it's pretty safe even if it's installed because it simply won't work. However, Apple's Safari supported NPAPI plug-ins right up to v11 but for reference, Apple automatically disabled the Java plug-in by default from around 2014 onwards (if I remember correctly) even if it was installed - you had to specifically turn it on to get it to work.
Information on/instructions for removing/disabling the Java plug-in can be found in my Java Security article on MacStrategy.
Watch out though - there are two locations internet plug-ins can be found. Those are:
I'm planning on doing step-by-step instructions for virtualising OS X 10.8, OS X 10.11 and macOS 10.12 on MacStrategy. I know I've promised this before on MacStrategy, but FYI I do MacStrategy for free, in my own time, and simply ask for donations + utilise Amazon / Apple affiliate links - there's very little other tracking/advertising/revenue generation on MacStrategy. For the whole of 2018 I got a grand total of £35.75 in donations! So, I'll get around to doing those other virtualisation articles when paid work doesn't get in the way ;-) You can donate to me using the Donate button at the bottom left of the MacStrategy home page.