which java # or readlink -f $(which java) Linux allows multiple JREs side-by-side. Use update-alternatives (Debian/Ubuntu) or manually set JAVA_HOME . Using update-alternatives (Debian/Ubuntu) # List available Java runtimes sudo update-alternatives --config java Manually register a new JRE sudo update-alternatives --install /usr/bin/java java /opt/jre-17/bin/java 1700 Manual JRE Switching (any distro) Set environment variables per user in ~/.bashrc or ~/.profile :
A: Some JDK packages include a full JRE, and the java binary is the same.
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64 /usr/lib/jvm/java-11-openjdk-amd64/ ├── bin/ # java, keytool, etc. ├── lib/ # core libraries (rt.jar, modules, etc.) ├── conf/ # security, logging, net properties ├── legal/ # licenses and notices └── release # version info 10. Testing JRE with a Sample Java Application Create a simple Java program to verify execution:
dirname $(dirname $(readlink -f $(which java)))
# Install Eclipse Temurin 17 JRE wget -O /tmp/temurin.deb https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.9%2B9/OpenJDK17U-jre_x64_linux_hotspot_17.0.9_9.deb sudo dpkg -i /tmp/temurin.deb For RPM-based systems, replace .deb with .rpm . After installation, verify:
Jre Linux ((top)) May 2026
which java # or readlink -f $(which java) Linux allows multiple JREs side-by-side. Use update-alternatives (Debian/Ubuntu) or manually set JAVA_HOME . Using update-alternatives (Debian/Ubuntu) # List available Java runtimes sudo update-alternatives --config java Manually register a new JRE sudo update-alternatives --install /usr/bin/java java /opt/jre-17/bin/java 1700 Manual JRE Switching (any distro) Set environment variables per user in ~/.bashrc or ~/.profile :
A: Some JDK packages include a full JRE, and the java binary is the same. jre linux
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64 /usr/lib/jvm/java-11-openjdk-amd64/ ├── bin/ # java, keytool, etc. ├── lib/ # core libraries (rt.jar, modules, etc.) ├── conf/ # security, logging, net properties ├── legal/ # licenses and notices └── release # version info 10. Testing JRE with a Sample Java Application Create a simple Java program to verify execution: which java # or readlink -f $(which java)
dirname $(dirname $(readlink -f $(which java))) After installation, verify:
# Install Eclipse Temurin 17 JRE wget -O /tmp/temurin.deb https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.9%2B9/OpenJDK17U-jre_x64_linux_hotspot_17.0.9_9.deb sudo dpkg -i /tmp/temurin.deb For RPM-based systems, replace .deb with .rpm . After installation, verify:
