pjosalgado

1. Convert our ".jks" file to ".p12" (PKCS12 keystore format): 
keytool -importkeystore -srckeystore { java-keystore.jks } -destkeystore { pkcs12-keystore.p12 } -deststoretype PKCS12

2. Extract pem (certificate) from ".p12" keystore file: 
openssl pkcs12 -nokeys -in { pkcs12-keystore.p12 } -out { certificate-chain.pem }

3. Extract unencrypted key file from ".p12" keystore file: 
openssl pkcs12 -nocerts -nodes -in { pkcs12-keystore.p12 } -out { unencrypted-key.key }