You don't need to down grade. You can run more than one version of Java on MacOS. You can set the version of your terminal with this command in MacOS.

# List Java versions installed
/usr/libexec/java_home -V

# Java 11
export JAVA_HOME=$(/usr/libexec/java_home -v 11)

# Java 1.8
export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)

# Java 1.7
export JAVA_HOME=$(/usr/libexec/java_home -v 1.7)

# Java 1.6
export JAVA_HOME=$(/usr/libexec/java_home -v 1.6)

You can set the default value in the .bashrc, .profile, or .zprofile

That does not seem to be accurate any more.

I just managed to downgrade both JRE and compiler from Java 8 to 7 by looking into /Library/Java/JavaVirtualMachines, and moving away the directory with the highest version number, e.g.

sudo mv jdk1.8.0.jdk ~/Desktop/

First run /usr/libexec/java_home -V which will output something like the following:

Matching Java Virtual Machines (3):
1.8.0_05, x86_64:   "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home
1.6.0_65-b14-462, x86_64:   "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
1.6.0_65-b14-462, i386: "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home

/Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home

Pick the version you want to be the default (1.6.0_65-b14-462 for arguments sake) then:

export JAVA_HOME=`/usr/libexec/java_home -v 1.6.0_65-b14-462` or you can specify just the major version, if it's unique, like

export JAVA_HOME=`/usr/libexec/java_home -v 1.8` Now when you run java -version you will see:

java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)

Just add the export JAVA_HOME… line to your shell’s init file.

Welcome to SO!

Even though you already solved it, using sdkman greatly reduces stress if you want to switch regularly between versions.

Install another JDK

You can install multiple JDKs on your Mac. You can have a JDK for Java 11 as well as a JDK for Java 17. And perhaps you might want another JDK for the new Java 21 that arrived yesterday. These can all live together, side-by-side.

Each JDK is just a folder full of files. You can add JDKs, and delete JDKs, at will.

The environment variable JAVA_HOME is a hint various software as to which JDK you would like to use by default.

You might find a feature within Android Studio to install another JDK. (At least the sibling product, IntelliJ, offers such a feature.)

Configure project

Within your project in Android Studio, you need to set some settings to indicate which of your installed JDKs should be used for compiling, building, and executing your app. See the Android Studio documentation.

SDKMAN!

Personally, I find it easiest to install SDKMAN!, a bunch of shell scripts that manage installing/uninstalling JDKs (and other such kits). This works well on macOS.

SDKMAN! is designed to be utterly simple to use.

On a console such as Terminal.app, execute:

• sdk list java
  See a list of all JDK products from vendors who chose to submit their data to the SDKMAN! database. From this list you copy the exact name of the JDK product you want to install. The list of products indicates any you have currently installed.
• sdk install java product_name_goes_here
  Install the JDK product of your choosing. Takes a moment to download and install. At the end, SDKMAN! prompts you to specify whether you want to make this newly installed JDK the default.
• sdk uninstall java product_name_goes_here
  Removes that particular JDK product from your Mac.

I had this same problem: I had Java 8 installed, but later installed 10. Then, I removed 10, and when I launched a jar from the terminal it would run in version 8, and when I checked the version with java -version in the terminal I would get back java version "1.8.0_181. However when I ran a .jar from the Finder, it would run in v.10, and also if I went to the Java preference pane the version was listed as version 10. This was undesirable: I was trying to remove v10 completely.

Then, I deleted JavaAppletPlugin with rm /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin and reinstalled Java SE JDK 8 from online, and lo! it works now. When I run .jar, they run in Java 8.

I realize you mentioned this in your first step, but I infer that you didn't do this step? If I'm wrong about that then you've got a different problem. But this solved mine.

If anyone still cares about downgrading Java on Snow Leopard, the answer that advises removing Java manually and reinstalling from download or Snow Leopard DVD doesn't work for Snow Leopard, but it can be made to work.

Instead of using the freestanding Java packages on the DVD, use the app Pacifist to open the main Snow Leopard installer .pkg. Then search for "java" and install every item that matches (you can skip the JavaScript items, obviously). This fixes the error reported in the linked article (which is offline but available at archive.org):

"Error occurred during initialization of VM Unable to load native library: libjava.jnilib"

Apparently there are additional pieces to a functioning Java install not included in the separate .pkg files.