Как найти java home

asked May 3, 2014 at 6:20

echo $JAVA_HOME

export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64

9

$ jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));'
/opt/local/jdk1.7.0_76/jre

$ export JAVA_HOME="$(jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));')"

1

export JAVA_HOME=`type -p java|xargs readlink -f|xargs dirname|xargs dirname`

$ type -p java
/usr/bin/java

$ readlink -f /usr/bin/java
/usr/lib/jvm/java-8-oracle/bin/java

$ dirname /usr/lib/jvm/java-8-oracle/bin/java
/usr/lib/jvm/java-8-oracle/bin/

$ dirname /usr/lib/jvm/java-8-oracle/bin/
/usr/lib/jvm/java-8-oracle/

4

$ update-alternatives --query java | grep 'Value: ' | grep -o '/.*/jre'

$ export JAVA_HOME="$(update-alternatives --query java | grep 'Value: ' | grep -o '/.*/jre')"

1

update-alternatives --query java | grep 'Value: ' | sed 's/Value: (.*)/bin/java/1/'

## e.g. returns  </opt/Oracle_Java/jre1.8.0_202> 
## if            </etc/alternatives/java>  points to 
##               </opt/Oracle_Java/jre1.8.0_202/bin/java>

export JAVA_HOME="$(update-alternatives --query java | grep 'Value: ' | sed 's/Value: (.*)/bin/java/1/')"

2

8

java -XshowSettings:properties -version 2>&1 > /dev/null | grep 'java.home'

java -XshowSettings:properties -version 2>&1 | findstr "java.home"

5

7

sudo find /usr/ -name *jdk

/usr/lib/jvm/java-6-openjdk
/usr/lib/jvm/java-1.6.0-openjdk

2

2

0

java -XshowSettings:properties -version 2>&1 
   | sed '/^[[:space:]]*java.home/!d;s/^[[:space:]]*java.home[[:space:]]*=[[:space:]]*//'

2

• Windows

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• macOS

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• Linux

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• Video

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• Tips

Things You Should Know

• Before you can set JAVA_HOME, you’ll need the full path to your JDK or JRE installation.
• Once you set the JAVA_HOME environment variable, you can run the command echo $JAVA_HOME to see the new path.
• To set the Java home and path on Linux or macOS permanently (even after a reboot), add the environment variables to your .bashrc or .zshrc file.

1. 

   1

   Find your Java installation directory. Assuming that you didn’t change the path for the JDK or JRE during installation is not changed, it should be in a directory under C:Program FilesJava. There are a few ways to find the full path:

   • Open File Explorer, click This PC in the left panel, then navigate to C:Program FilesJava. The directory you’re looking for should have the name of the JDK version, such as C:Program FilesJavajdk-19.
   • If you installed the JRE instead of the JDK, you’ll have something like C:Program FilesJavajre1.8.0_351 instead.
   • You can also open the command prompt and run the command wmic product where "Name like '%%Java%%'" get installlocation,Name. This will tell you the full path of the JDK, even if you haven’t yet set JAVA_HOME.

2. 

   2

   Open your Advanced System Settings. Here’s how:

   • Press the Windows key on your keyboard and type advanced system.
   • Click View advanced system settings in the search results.

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3. 

   3

   Click the Environment Variables button. You’ll see it at the bottom-right corner of the System Properties window.

4. 

   4

   Click the New… button under «User variables.» You’ll have two sections on this window—»User variables» and «System variables.» You’ll want to make sure you’re clicking New under the first box (User variables).

   • If you have multiple installations of the JDK and want to change JAVA_HOME to your new installation, select the current JAVA_HOME user variable and click Edit… instead.

5. 

   5

   Type JAVA_HOME as the «Variable name.»

   • If you’re editing the current JAVA_HOME path, you’ll already have JAVA_HOME here. So, you can skip this step.

6. 

   6

   Enter the full path to your JDK or JRE installation. For example, if the path is C:Program FilesJavajdk-19, enter that full path into the «Variable value» field.^[1]
   

   • If you’re adding a second path to JAVA_HOME, just type a semicolon (;) after the first path, then enter the second path.
   • If you’re replacing an old JAVA_HOME path, just delete the current path and enter the new one.

7. 

   7

   Click OK. This takes you back to the Environment Variables window.

8. 

   8

   Select the Path user variable and click Edit. You should already have a variable in the «User variables» section called «Path.» To make sure you can run the Java binaries, you’ll need to edit your path to add the location of the JDK bin directory.

   • If you want other users on this PC to be able to access Java binaries from the command line, repeat this step for the «Path» variable under «System variables» as well.

9. 

   9

   Append the path to your Java /bin directory to the end of the path. You’ll already have at least one directory in your path, which needs to stay in place. Here’s how to add the Java bin directory:

   • Click the New button at the top.
   • Enter the full path to the JRE or JDK with bin at the end. For example, C:Program FilesJavajdk-19bin or C:Program FilesJavajre1.8.0_351bin.
   • Click OK.

10. 

    10

    Click OK on all subsequent windows. This updates your JAVA_HOME variable and adds the Java binaries to your path.

    • You won’t need to restart your computer for the changes to take effect, but you will need to relaunch any apps that were trying to access Java.
    • Open a new command prompt window and run the command echo %JAVA_HOME% to display the new path to JAVA_HOME.
      • Make sure this is a new command prompt window. If you still have the same window open, the command will fail because it doesn’t have the new environment variables.

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1. 

   1

   Open a Terminal window. To open Terminal, search for Terminal in Spotlight. Or, you can open Finder, click the Go menu, select Utilities, and choose the Terminal app.

2. 

   2

   Type /usr/libexec/java_home and press ⏎ Return. This handy utility that comes preinstalled on macOS will tell you the full path to your Java installation, which you’ll need to set JAVA_HOME.

   • If you have more than one Java installation and want to see the paths to all of them, use /usr/libexec/java_home -V instead.

3. 

   3

   Copy the path and paste it somewhere handy. Highlight the path to the Java installation you want to use as JAVA_HOME, press Cmd + V to copy it, then paste it into a sticky note or text file.

4. 

   4

   Open your .zshrc file in a text editor. As long as you’re using macOS Catalina or later, you’ll be using the zsh shell by default, which means you’ll add JAVA_HOME and the path to your .zshrc file.^[2]
   If you’re using an earlier version of macOS (or prefer the bash shell), replace .zshrc with .bashrc in these commands instead. Here’s the easiest way to open the file:

   • Type cd ~ and press Return.
   • Type open .zshrc and press Return. This should open the file in a text editor.
   • If the file is not found, type echo > .zshrc and press Return. Then, run open .zshrc again.

5. 

   5

   Add these lines to the bottom of the file. Adding these lines ensures that JAVA_HOME will be set correctly even after you log off or open another window. If the file has existing contents, just scroll down past them to enter the following text on individual lines:

   • export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-17.0.1.jdk/Contents/Home
     • Replace /Library/Java/JavaVirtualMachines/jdk-17.0.1.jdk/Contents/Home with the full path to the /Contents/Home directory of your Java installation if it’s different.
   • export PATH=$JAVA_HOME/bin:$PATH
   • Save the file and exit the text editor when you’re finished.

6. 

   6

   Type source .zshrc and press ⏎ Return. Once you’ve edited your profile, this command ensures that your environment variables will be updated for the current terminal window (and any other windows you open from now on).

7. 

   7

   Type echo $JAVA_HOME and press ⏎ Return to confirm JAVA_HOME. You should now see the full path to JAVA_HOME.

   • If you had any other windows open that were attempting to find Java binaries, close and reopen them.
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1. 

   1

   Open a terminal window. If you’re logged in to your desktop environment, you can press Ctrl + Alt + T to launch a terminal window.

   • This method will work in just about any version of Linux, including Ubuntu and Redhat.

2. 

   2

   Find the location of your Java installation. One way you might find the Java install location is to run the which javac command, but this will only give you a symbolic link. Instead, run this command to find the location of the executable file:

   • readlink -f `which javac`
   • If that doesn’t work, try running update-alternatives --list java.
   • If neither of these commands works, run whereis java, which will usually result in a symbolic link like /usr/bin/java.
     • Once you get the directory, find out where it links using ls -la /bin/java.
     • If that points you to another directory, e.g., /etc/alternatives/java, run ls -la /etc/alternatives/java.
     • At that point, you should see a much longer directory, which is actually the home to the Java binaries. For example, usr/lib/jvm/java-11-openjdk-arm64/bin/java. This is the directory you want.

3. 

   3

   Set the JAVA_HOME path. Now that you have the location of Java, you can add the path to your .bashrc file (if you’re using the bash shell), .zshrc (for the zsh shell), or the equivalent for your shell.^[3]
   Run both of the following commands, replacing the path with the path to your JDK or JRE installation, and «bashrc» with your shell’s login script:

   • echo "export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-arm64" >> ~/.bashrc
   • echo "export PATH=$PATH:$JAVA_HOME/bin" >> ~/.bashrc

4. 

   4

   Type source .bashrc to apply the changes to the current terminal window. Though you’ve already set the home for Java and added the path to its binaries permanently, the changes won’t take effect in your current terminal window until you run this command.

   • At this point, you can run echo $JAVA_HOME to see the location of Java on your system.

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• In Linux, you can set JAVA__HOME for all users by editing the global .bashrc, which is located at /etc/bash.bashrc. Just use echo and replace ~/.bashrc with /etc/bash.bashrc.

• On both Linux and macOS, you can set the Java home in your .bash_profile or .zprofile if you prefer.