This class fixes older Java SSL setups which don't contain the correct root certificates to trust Let's Encrypt
https endpoints.
It uses a secondary JKS keystore: lekeystore.jks, which contains the two root certificate keys as documented here:
https://letsencrypt.org/certificates/
To create the keystore, the following commands were run:
keytool -import -alias letsencryptisrgx1 -file isrgrootx1.pem -keystore lekeystore.jks -storetype jks -storepass supersecretpassword -v
keytool -import -alias identrustx3 -file identrustx3.pem -keystore lekeystore.jks -storetype jks -storepass supersecretpassword -v
The PEM files were obtained from the above URL.