#!/bin/bash
###  JRE_DOWNLOAD contains the download URL to the target OpenJDK tar archive
###  The example below upgrades the JRE to OpenJDK JRE 17.0.8+7

JRE_DOWNLOAD=https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.8%2B7/OpenJDK17U-jre_x64_linux_hotspot_17.0.8_7.tar.gz

#####  Do not modify below this point  ######

JRE_HOME=$(cat /etc/systemd/system/webapp.service | grep JRE_HOME | cut -f 3 -d '=')
JRE_OWNER=$(stat -c "%U:%G" $JRE_HOME)
JRE_TAR=$(basename $JRE_DOWNLOAD)
mkdir _tmp
cd _tmp
##   Download OpenJDK JRE
wget $JRE_DOWNLOAD

##  Remove current JRE_HOME
rm -fr $JRE_HOME

##  Extract OpenJDK
mkdir -p $JRE_HOME
tar -xf $JRE_TAR -C $JRE_HOME --strip-components=1
chown -R $JRE_OWNER $JRE_HOME

cd ..
rm -fr _tmp