Example how download latest JDK tar for Linux x64 platform programmatically

download_jdk.sh

#!/usr/bin/env bash
#
# AUTHOR: Daniel Leybovich

BASE_URL="http://www.oracle.com"
PLATFORM="Linux x64"                
ARCHIVE="tar.gz"

# get link to download page
SUFFIX=$(curl "${BASE_URL}/technetwork/java/javase/downloads/index.html" 2>/dev/null | grep 'name="JDK8"' | sed -nr 's/.*href="([^"]+)".*/\1/p')
LINK="${BASE_URL}${SUFFIX}"

# extract from download page link to latest version
DOWNLOAD_LINK=$(curl "${LINK}" 2>/dev/null | grep "${PLATFORM}" | grep -v demos | grep "${ARCHIVE}" | sed  -nr 's/.*filepath":"([^"]+)".*/\1/p')

LATEST_VERSION=$(echo "${DOWNLOAD_LINK}" | sed -rn 's:.*/(8u[^/]+)/.*:\1:p')
CURRENT_VERSION=$(java -version 2>&1 | grep -m1 build | sed -rn 's/.*build ([^\)]+)\)/\1/p')

echo '-----------------------------------------------------'
echo "CURRENT VERSION  : ${CURRENT_VERSION}"
echo "LATEST VERSION   : ${LATEST_VERSION}"
echo "DOWNLOAD LINK    : ${DOWNLOAD_LINK}"
echo '-----------------------------------------------------'

# download latest JDK
#wget -c --header "Cookie: oraclelicense=accept-securebackup-cookie" "${DOWNLOAD_LINK}" 2>/dev/null

# done
exit 0