How to Set JAVA_HOME Environment Variable

JAVA_HOME is an environment variable that points to your Java installation directory. Many Java-based applications and build tools (Maven, Gradle, Tomcat) require this variable to be set correctly.

Why Set JAVA_HOME?

  • Required by build tools: Maven, Gradle, and Ant need it to find Java
  • Application servers: Tomcat, JBoss, and others use it
  • IDE compatibility: Ensures consistent Java version across tools
  • Script automation: Makes Java location consistent across systems

Finding Your Java Installation

Linux

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# Find Java installation path
which java

# Get full path (follows symlinks)
readlink -f $(which java)

# Or use update-alternatives
update-alternatives --list java

Common locations:

  • /usr/lib/jvm/java-11-openjdk-amd64
  • /usr/lib/jvm/java-17-openjdk-amd64
  • /usr/java/jdk-17.0.1

macOS

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# Find Java home using java_home utility
/usr/libexec/java_home

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

# Get path for specific version
/usr/libexec/java_home -v 17

Common locations:

  • /Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home
  • /Applications/Android Studio.app/Contents/jbr/Contents/Home

Windows

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# From Command Prompt
where java

# From PowerShell
(Get-Command java).Path

Common locations:

  • C:\Program Files\Java\jdk-17
  • C:\Program Files\OpenJDK\jdk-17.0.1
  • C:\Program Files\Eclipse Adoptium\jdk-17.0.1-hotspot

Setting JAVA_HOME

Linux

Temporary (Current Session Only)

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export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH=$PATH:$JAVA_HOME/bin

Permanent (All Sessions)

Add to ~/.bashrc or ~/.zshrc:

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# Open your shell config file
nano ~/.bashrc  # or ~/.zshrc for Zsh

# Add these lines at the end
export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH=$PATH:$JAVA_HOME/bin

# Save and reload
source ~/.bashrc  # or source ~/.zshrc

System-wide (All Users)

Create a file in /etc/profile.d/:

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# Create environment file
sudo nano /etc/profile.d/java.sh

# Add this content
export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH=$PATH:$JAVA_HOME/bin

# Make it executable
sudo chmod +x /etc/profile.d/java.sh

# Reload
source /etc/profile.d/java.sh

macOS

Using Shell Configuration

Add to ~/.zshrc (default shell on modern macOS):

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# Open Zsh config
nano ~/.zshrc

# Add these lines
export JAVA_HOME=$(/usr/libexec/java_home)
export PATH=$JAVA_HOME/bin:$PATH

# Save and reload
source ~/.zshrc

For Specific Java Version

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# Java 17
export JAVA_HOME=$(/usr/libexec/java_home -v 17)

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

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

For Android Studio’s JDK

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export JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home"
export PATH=$JAVA_HOME/bin:$PATH

Windows

Using System Properties (GUI)

  1. Open Start Menu, search for “Environment Variables”
  2. Click Edit the system environment variables
  3. Click Environment Variables button
  4. Under System variables, click New
  5. Set:
    • Variable name: JAVA_HOME
    • Variable value: C:\Program Files\Java\jdk-17 (your Java path)
  6. Click OK
  7. Find Path variable, click Edit
  8. Click New and add: %JAVA_HOME%\bin
  9. Click OK on all dialogs
  10. Restart any open Command Prompts

Using Command Prompt (Admin)

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setx JAVA_HOME "C:\Program Files\Java\jdk-17" /M
setx PATH "%PATH%;%JAVA_HOME%\bin" /M

Note: /M sets system-wide. Remove it for user-only.

Using PowerShell (Admin)

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[System.Environment]::SetEnvironmentVariable("JAVA_HOME", "C:\Program Files\Java\jdk-17", "Machine")
$path = [System.Environment]::GetEnvironmentVariable("PATH", "Machine")
[System.Environment]::SetEnvironmentVariable("PATH", "$path;%JAVA_HOME%\bin", "Machine")

Verify Installation

After setting JAVA_HOME, verify it’s working:

Linux/macOS

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# Check JAVA_HOME value
echo $JAVA_HOME

# Verify Java is accessible
java -version

# Verify javac (compiler) is accessible
javac -version

# Full test
$JAVA_HOME/bin/java -version

Expected output:

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openjdk version "17.0.1" 2021-10-19
OpenJDK Runtime Environment (build 17.0.1+12)
OpenJDK 64-Bit Server VM (build 17.0.1+12, mixed mode)

Windows

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# Check JAVA_HOME value
echo %JAVA_HOME%

# Verify Java is accessible
java -version

# Verify javac (compiler) is accessible
javac -version

Common Issues

“JAVA_HOME is not defined”

Solution: Ensure you’ve reloaded your shell or restarted your terminal after setting the variable.

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# Linux/macOS - reload config
source ~/.bashrc  # or ~/.zshrc

# Windows - restart Command Prompt/PowerShell

“command not found: java” after setting JAVA_HOME

Solution: Make sure you also added $JAVA_HOME/bin to your PATH.

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# Check if JAVA_HOME/bin is in PATH
echo $PATH | grep "$JAVA_HOME"

# If not, add it
export PATH=$PATH:$JAVA_HOME/bin

Wrong Java version being used

Solution: Check if multiple Java installations exist and PATH order.

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# Find all Java locations
which -a java

# Check PATH order
echo $PATH

# Ensure JAVA_HOME/bin appears early in PATH
export PATH=$JAVA_HOME/bin:$PATH  # Note: JAVA_HOME/bin comes FIRST

Maven/Gradle still can’t find Java

Solution: Some tools need explicit JAVA_HOME. Verify the path points to JDK, not JRE:

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# Should show JDK directory with 'bin', 'lib', 'include', etc.
ls $JAVA_HOME

# Must contain javac (Java compiler)
ls $JAVA_HOME/bin/javac

Multiple Java Versions

If you need to switch between Java versions:

Linux - Using update-alternatives

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# List available Java versions
sudo update-alternatives --config java

# Select the version you want by entering the number

macOS - Using jenv

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# Install jenv
brew install jenv

# Add to shell config
echo 'export PATH="$HOME/.jenv/bin:$PATH"' >> ~/.zshrc
echo 'eval "$(jenv init -)"' >> ~/.zshrc

# Add Java versions
jenv add /Library/Java/JavaVirtualMachines/jdk-11.jdk/Contents/Home
jenv add /Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home

# Set global version
jenv global 17

# Set local version (project-specific)
cd your-project
jenv local 11

Windows - Manual switching

Create batch files for each version:

java11.bat:

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@echo off
setx JAVA_HOME "C:\Program Files\Java\jdk-11" /M
echo Java 11 is now active

java17.bat:

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@echo off
setx JAVA_HOME "C:\Program Files\Java\jdk-17" /M
echo Java 17 is now active

Quick Reference

Linux/macOS

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# Set JAVA_HOME temporarily
export JAVA_HOME=/path/to/java
export PATH=$JAVA_HOME/bin:$PATH

# Set JAVA_HOME permanently (add to ~/.bashrc or ~/.zshrc)
export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH=$JAVA_HOME/bin:$PATH

# Verify
echo $JAVA_HOME
java -version

Windows (Command Prompt)

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# Set JAVA_HOME permanently (run as Admin)
setx JAVA_HOME "C:\Program Files\Java\jdk-17" /M
setx PATH "%PATH%;%JAVA_HOME%\bin" /M

# Verify (restart CMD first)
echo %JAVA_HOME%
java -version

macOS with Android Studio JDK

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# Add to ~/.zshrc
export JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home"
export PATH=$JAVA_HOME/bin:$PATH

# Reload
source ~/.zshrc

Additional Environment Variables

If you’re also developing Android apps, you might need:

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# Android SDK
export ANDROID_HOME=$HOME/Library/Android/sdk
export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

# Or on Linux
export ANDROID_HOME=$HOME/Android/Sdk
export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

For Node.js version management with NVM:

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# Add to ~/.bashrc or ~/.zshrc
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"

Conclusion

Setting JAVA_HOME correctly ensures your Java development tools work smoothly. Remember to:

  • Use the JDK directory, not JRE
  • Add $JAVA_HOME/bin to your PATH
  • Reload your shell after making changes
  • Verify with java -version and echo $JAVA_HOME

For projects requiring specific Java versions, consider using version managers like jenv (macOS/Linux) or SDKMAN! (all platforms).