Install Let's Encrypt CA to JRE keystore, for you know, older JIRA for example

install-letsencrypt-to-older-jre.sh

#!/bin/bash
set -e

STORE_PASS=changeit

JAVA_HOME=${1-text}
[ $# -eq 0 ] && { echo "Usage: sudo $0 \$(/usr/libexec/java_home -v '1.8*')" ; exit 1; }

KEYSTORE=$JAVA_HOME/jre/lib/security/cacerts

wget https://letsencrypt.org/certs/letsencryptauthorityx1.der
wget https://letsencrypt.org/certs/letsencryptauthorityx2.der
wget https://letsencrypt.org/certs/lets-encrypt-x1-cross-signed.der
wget https://letsencrypt.org/certs/lets-encrypt-x2-cross-signed.der
wget https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.der
wget https://letsencrypt.org/certs/lets-encrypt-x4-cross-signed.der

# to be idempotent
"$JAVA_HOME"/jre/bin/keytool -delete -alias isrgrootx1 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true
"$JAVA_HOME"/jre/bin/keytool -delete -alias isrgrootx2 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true
"$JAVA_HOME"/jre/bin/keytool -delete -alias letsencryptauthorityx1 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true
"$JAVA_HOME"/jre/bin/keytool -delete -alias letsencryptauthorityx2 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true
"$JAVA_HOME"/jre/bin/keytool -delete -alias letsencryptauthorityx3 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true
"$JAVA_HOME"/jre/bin/keytool -delete -alias letsencryptauthorityx4 -keystore "$KEYSTORE" -storepass $STORE_PASS 2> /dev/null || true

"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias isrgrootx1 -file letsencryptauthorityx1.der
"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias isrgrootx2 -file letsencryptauthorityx2.der
"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias letsencryptauthorityx1 -file lets-encrypt-x1-cross-signed.der
"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias letsencryptauthorityx2 -file lets-encrypt-x2-cross-signed.der
"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias letsencryptauthorityx3 -file lets-encrypt-x3-cross-signed.der
"$JAVA_HOME"/jre/bin/keytool -trustcacerts -keystore "$KEYSTORE" -storepass $STORE_PASS -noprompt -importcert -alias letsencryptauthorityx4 -file lets-encrypt-x4-cross-signed.der

rm -f letsencryptauthorityx1.der letsencryptauthorityx2.der lets-encrypt-x1-cross-signed.der lets-encrypt-x2-cross-signed.der lets-encrypt-x3-cross-signed.der lets-encrypt-x4-cross-signed.der