swapnull-in

# Convert the .cer file into a .pem file:
$ openssl x509 -in aps.cer -inform der -out apns_cert_prod.pem

# Convert the private key’s .p12 file into a .pem file:
$ openssl pkcs12 -nocerts -in aps_production.p12 -out apns_key_prod.pem

# Finally, combine the certificate and key into a single .pem file
$ cat apns_cert_prod.pem apns_key_prod.pem > ck_prod.pem

# At this point it’s a good idea to test whether the certificate works.

swapnull-in

# Convert the .cer file into a .pem file:
$ openssl x509 -in aps_development.cer -inform der -out apns_cert_dev.pem

# Convert the private key’s .p12 file into a .pem file:
$ openssl pkcs12 -nocerts -in aps_development.p12 -out apns_key_dev.pem

# Finally, combine the certificate and key into a single .pem file
$ cat apns_cert_dev.pem apns_key_dev.pem > ck_dev.pem

# At this point it’s a good idea to test whether the certificate works.

swapnull-in

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;