Defining Java's version by alternatives tool

java_update-alternatives.sh

#!/bin/bash
#
# By: Samuel Maciel Sampaio <[email protected]> [20150122]
# Defining Java's version by alternatives tool

# Set HERE the REAL PATH to JDK FILES UNCOMPRESSED AND JAVA version you want to configure!
REAL_JDK_PATH="/usr/lib/jvm/java-1.8.0-oraclejdk-1.8.0_66"

JAVA_VERSION="1.8.0_66"

ALTERNATIVES_TOOL=$(which update-alternatives 2>/dev/null)
if [ -z "${ALTERNATIVES_TOOL}" ];
then
    ALTERNATIVES_TOOL=$(which alternatives 2>/dev/null)
    if [ -z "${ALTERNATIVES_TOOL}" ];
    then
        echo "Error: Unable to find 'alternatives' program... please install them or put in your \$PATH"
    fi
fi

ALTERNATIVES_PRIORITY="99999999"

JAVA_BINS=$(sudo ls -1 ${REAL_JDK_PATH}/bin | sed s/'java$'/''/g | grep -v 'keytool')

ALTERNATIVE_CMD="${ALTERNATIVES_TOOL} --install /usr/bin/java java ${REAL_JDK_PATH}/bin/java ${ALTERNATIVES_PRIORITY}"
for JAVA_BIN in $JAVA_BINS;
do
  ALTERNATIVE_CMD="${ALTERNATIVE_CMD} --slave /usr/bin/${JAVA_BIN} ${JAVA_BIN} ${REAL_JDK_PATH}/bin/${JAVA_BIN}"

  sudo ${ALTERNATIVES_TOOL} --remove-all ${JAVA_BIN} > /dev/null 2>&1
done

OTHER_MASTERS="keytool"
for MASTER_BIN in $OTHER_MASTERS;
do
  # sudo ${ALTERNATIVES_TOOL} --remove-all ${MASTER_BIN} > /dev/null 2>&1

  sudo ${ALTERNATIVES_TOOL} --install /usr/bin/${MASTER_BIN} ${MASTER_BIN} ${REAL_JDK_PATH}/bin/${MASTER_BIN} ${ALTERNATIVES_PRIORITY}
done

sudo ${ALTERNATIVE_CMD}

sudo ${ALTERNATIVES_TOOL} --set java ${REAL_JDK_PATH}/bin/java

sudo ${ALTERNATIVES_TOOL} --display java

echo "Current JAVA version: `java -version`"