oh-my-zsh plugin that sets the JAVA_HOME and path to activate a specified version of a JDK (installed via webupd8 packages). Install in .oh-my-zsh/custom/plugins/use-java/use-java.plugin.zsh

use-java.plugin.zsh

function _use-java_usage() {
  echo "Usage use-java VERSION"
  echo 'Set the Oracle JDK version to use for the current session.'
  echo ''
  echo 'The VERSION is the JDK version to use such that'
  echo 'the directory /usr/lib/jvm/java-${VERSION}-oracle'
  echo 'will be set as JAVA_HOME and the corresponding bin/'
  echo 'directory will be added to the front of PATH.'
}

function use-java() {
  if [[ -z "$1" ]]; then
    _use-java_usage
    return -1
  fi

  local JVM_DIR="/usr/lib/jvm/java-$1-oracle"
  if [[ -d ${JVM_DIR} ]]; then
    echo "Setting session JDK to ${JVM_DIR}"
    export JAVA_HOME=${JVM_DIR}
    export PATH=${JVM_DIR}/bin:${PATH}
    java -version
  else
    echo "No Oracle JDK found at ${JVM_DIR}"
    return -1
  fi
}