Error java home environment variable is not set

JAVA_HOME="C:Program FilesJavajdkxxx"

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Do not include bin in your JAVA_HOME env variable

JAVA_HOME=C:Program FilesJavajdk1.7.0_07

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The JAVA_HOME should point to the JDK home rather than the JRE home if you are going to be compiling stuff, likewise — I would try and install the JDK in a directory that doesn’t include a space. Even if this is not your problem now, it can cause problems in the future!

You are pointing your JAVA_HOME to the JRE which is the Java Runtime Environment. The runtime environment doesn’t have a java compiler in its bin folder.
You should download the JDK which is the Java Development Kit. Once you’ve installed that, you can see in your bin folder that there’s a file called javac.exe. That’s your compiler.

JAVA_HOME="/usr/lib/jvm/open-jdk"

source /etc/environment

echo $JAVA_HOME

source /etc/environment

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В этом руководстве мы поговорим об исключении, которое Maven выдает при неправильной настройке:JAVA_HOME should point to a JDK, not a JRE.

Maven — мощный инструмент для создания кода. Мы посмотрим изнутри, чтобы понять, почему происходит эта ошибка, и посмотрим, как ее устранить.

После установки Maven выполняетсяwe have to set the JAVA_HOME environment variable, so the tool knows where to find the JDK commands. Цели Maven запускают соответствующие команды Java в исходном коде проекта.

Например, наиболее распространенным сценарием является компиляция кода путем выполнения командыjavac.

ЕслиJAVA_HOME is not pointing to a valid JDK installation, Maven выдает ошибку при каждом выполнении:

mvn -version

# Output... 
The JAVA_HOME environment variable is not defined correctly
This environment variable is needed to run this program
NB: JAVA_HOME should point to a JDK, not a JRE

Как Maven проверяет путьJAVA_HOME?

Перед запуском любых целей введитеMaven checks for the existence of the java command по пути, указанномуJAVA_HOME, или запросив у ОС установку JDK по умолчанию. If the executable is not found, Maven terminates with the error.

Вот проверка исполняемого файлаmvn для Linux (Apache Maven v3.5.4):

if [ -z "$JAVA_HOME" ] ; then
    JAVACMD=`which java`
else
    JAVACMD="$JAVA_HOME/bin/java"
fi
 
if [ ! -x "$JAVACMD" ] ; then
    echo "The JAVA_HOME environment variable is not defined correctly" >&2
    echo "This environment variable is needed to run this program" >&2
    echo "NB: JAVA_HOME should point to a JDK not a JRE" >&2
    exit 1
fi

Эта проверка на первый взгляд может показаться разумной, но мы должны учитывать, чтоboth JDK and JRE have a bin folder and both contain an executable java file.

Следовательно, этоpossible to configure JAVA_HOME to point to a JRE installation, hiding this particular error and causing problems at a later stage.. В то время как основная цель JRE — запуск кода Java,the JDK can also compile and debug among other important differences.

По этой причине командаmvn compile не сработает, как мы увидим в следующем подразделе.

Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T18:41:47Z)
Maven home: /opt/apache-maven-3.6.0
Java version: 1.8.0_191, vendor: Oracle Corporation, runtime: /usr/lib/jvm/java-8-openjdk-amd64/jre
Default locale: en, platform encoding: UTF-8
OS name: "linux", version: "4.15.0-42-generic", arch: "amd64", family: "unix"

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project my-app: Compilation failure
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

    maven-compiler-plugin
    3.7.0

    maven-compiler-plugin
    3.7.0
    
        true
        /usr/lib/jvm/java-11-openjdk-amd64/bin/javac
    

check if JAVA_HOME points to an actual JDK.  довольно просто. Мы можем либо распечатать его содержимое в терминале, либо запустить одну из следующих команд оболочки:

> $JAVA_HOME/bin/javac -version

> bash: /bin/javac: No such file or directory

%JAVA_HOME%binjavac -version

> The system cannot find the path specified.

Прежде всего, нам нужно знать, где найти наш JDK:

В этом кратком руководстве мы обсудили ошибку «JAVA_HOME should point to a JDK not a JRE” Maven и изучили ее первопричину.

Наконец, мы обсудили, как проверить вашу переменную средыJAVA_HOME и как убедиться, что она указывает на JDK.

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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.

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   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.

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

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   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.

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   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.

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   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.

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

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   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.

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   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.

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    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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   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.

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   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.

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   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.

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   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.

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   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.

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   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).

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   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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   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.

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   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.

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   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

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   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.