Where to set JAVA_HOME in Ubuntu

Question

I am trying to configure Tomcat to know where JAVA_HOME is. I am used to Windows :) ...which file should I edit to add the Java info, and where is it located?

Answer 1

For development work:

If your shell is bash (echo $SHELL -> /bin/bash) you may want to add a JAVA_HOME entry in /home/<user>/.bashrc. However, note that if you only work with one Java version, you should install the package and no explicit JAVA_HOME setting should be necessary for most scenarios.

Also, it is sometimes convenient to do something like this:

$ JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun mvn package

Which means to set JAVA_HOME for this command only.

Answer 2

Using Oracle JDK, here is how I set mine. Don't forget the "-p" in your export command.

# Set the JAVA_HOME variable
function set_java_home {
  echo "Searching for java ..."
  if [ -z $JAVA_HOME ]; then
      echo "Using default value for JAVA_HOME: /usr/java/default"
      JAVA_HOME=/usr/java/default
  fi
  export -p JAVA_HOME
  echo $JAVA_HOME > java.home.config
  sudo rm /etc/alternatives/java
  sudo ln -s $JAVA_HOME/bin/java /etc/alternatives/java
  echo "JAVA_HOME variable set to $JAVA_HOME and /etc/alternatives set."
}
if [ -f java.home.config ]; then
  JAVA_HOME=$(<java.home.config)
else
  JAVA_HOME_CANDIDATES=$(find /usr -type d -name '*jdk1.6*')
  echo "Found the following candidates for JAVA_HOME. Pick one: "
  echo "---"
  echo $JAVA_HOME_CANDIDATES
  echo "---"
  read USER_SUBMITTED_JAVA_HOME
  echo "You chose $USER_SUBMITTED_JAVA_HOME ."
  JAVA_HOME=${USER_SUBMITTED_JAVA_HOME}
fi
set_java_home