How do I check if the Java JDK is installed on Mac? - macos

Question

How do you check if Java SDK is installed on a Mac?
Is there a command line for this?

Answer 1

javac -version in a terminal will do

Answer 2

You can leverage the java_home helper binary on OS X for what you're looking for.
To list all versions of installed JDK:
$ /usr/libexec/java_home -V
Matching Java Virtual Machines (2):
1.8.0_51, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home
1.7.0_79, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home
To request the JAVA_HOME path of a specific JDK version, you can do:
$ /usr/libexec/java_home -v 1.7
/Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home
$ /usr/libexec/java_home -v 1.8
/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home
You could take advantage of the above commands in your script like this:
REQUESTED_JAVA_VERSION="1.7"
if POSSIBLE_JAVA_HOME="$(/usr/libexec/java_home -v $REQUESTED_JAVA_VERSION 2>/dev/null)"; then
# Do this if you want to export JAVA_HOME
export JAVA_HOME="$POSSIBLE_JAVA_HOME"
echo "Java SDK is installed"
else
echo "Did not find any installed JDK for version $REQUESTED_JAVA_VERSION"
fi
You might be able to do if-else and check for multiple different versions of java as well.
If you prefer XML output, java_home also has a -X option to output in XML.
$ /usr/libexec/java_home --help
Usage: java_home [options...]
Returns the path to a Java home directory from the current user's settings.
Options:
[-v/--version <version>] Filter Java versions in the "JVMVersion" form 1.X(+ or *).
[-a/--arch <architecture>] Filter JVMs matching architecture (i386, x86_64, etc).
[-d/--datamodel <datamodel>] Filter JVMs capable of -d32 or -d64
[-t/--task <task>] Use the JVM list for a specific task (Applets, WebStart, BundledApp, JNI, or CommandLine)
[-F/--failfast] Fail when filters return no JVMs, do not continue with default.
[ --exec <command> ...] Execute the $JAVA_HOME/bin/<command> with the remaining arguments.
[-R/--request] Request installation of a Java Runtime if not installed.
[-X/--xml] Print full JVM list and additional data as XML plist.
[-V/--verbose] Print full JVM list with architectures.
[-h/--help] This usage information.

Answer 3

Type in a terminal:
which javac
It should show you something like
/usr/bin/javac

Answer 4

Below command worked out pretty good:
javac -version
I also manually verified by navigating to the Java Folder on my Mac
/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk

Answer 5

/usr/bin/java_home tool returns 1 if java not installed.
So you can check if java is installed by the next way:
/usr/libexec/java_home &> /dev/null && echo "installed" || echo "not installed"

Answer 6

Open terminal.
run command to see:
javac -version
Also you can verify manually by going to the specific location and then check. To do this run below command in the mac terminal
cd /Library/Java/JavaVirtualMachines/
Then run ls command in the terminal again. Now you can see the jdk version & package if exists in your computer.

Answer 7

If you are on Mac OS Big Sur, then you probably have a messed up java installation.
I found info on how to fix the issue with this article:
https://knasmueller.net/how-to-install-java-openjdk-15-on-macos-big-sur
Download the .tar.gz file of the JDK on https://jdk.java.net/15/
Navigate to the download folder, and run these commands (move the .tar.gz file, extract it and remove it after extraction):
sudo mv openjdk-15.0.2_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
cd /Library/Java/JavaVirtualMachines/
sudo tar -xzf openjdk-15.0.2_osx-x64_bin.tar.gz
sudo rm openjdk-15.0.2_osx-x64_bin.tar.gz
Note: it might be 15.0.3 or higher, depending on the date of your download.
run /usr/libexec/java_home -v15 and copy the output
add this line to your .bash_profile or .zshrc file, depending on which shell you are using. You will probably have only one of these files existing in your home directory (~/.bash_profile or ~/.zshrc).
JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-15.0.2.jdk/Contents/Home
save the changes and make them effective right away by running:
source ~/.bash_profile or source ~/.zshrc
check that java is working - run java -v

Answer 8

Just type javac. If it is installed you get usage information, otherwise it would just ask if you would like to install Java.

Answer 9

Make sure you correctly define the project's JDK and restart IntelliJ (full restart).

Answer 10

On MAC find your JDK path by executing the command.
/usr/libexec/java_home