title: Error message: Installing OpenDaylight "java_home"
body: <p>I need to install OpenDaylight controller, I've followed the steps, but I got this error message</p>
  <pre><code>
  dalal@dalal:~$ sudo ./distribution-karaf-0.4.0-Beryllium/bin/karaf
  karaf: JAVA_HOME not set; results may vary
  ./distribution-karaf-0.4.0-Beryllium/bin/karaf: 242: [: Illegal number: 
  OpenJDK 64-Bit Server VM warning: Ignoring option UnsyncloadClass; support was removed in 11.0
  OpenJDK 64-Bit Server VM warning: Ignoring option MaxPermSize; support was removed in 8.0
  -Djava.endorsed.dirs=/usr/lib/jvm/java-11-openjdk-amd64/jre/lib/endorsed:/usr/lib/jvm/java-11-openjdk-amd64/lib/endorsed:/home/dalal/distribution-karaf-0.4.0-Beryllium/lib/endorsed is not supported. Endorsed standards and standalone APIs
  in modular form will be supported via the concept of upgradeable modules.
  Error: Could not create the Java Virtual Machine.
  Error: A fatal exception has occurred. Program will exit.
  </code></pre>
  <p><img src="https://i.stack.imgur.com/X02xV.png" alt="showing image" /></p>