Java APNS (Apple Push Notification Service) error

I am trying to use Java APNS - an open source project - to send push notifications to iPhones. I am getting an error, though.

I have used a .pem file as certificate. Should this have been a .p12 file? I am not sure what the difference is, but I read somewhere online that there is a difference between these file formats.

Here is the code:

   ApnsService service =
        APNS.newService()
            .withCert("gpk.pem", "XXXX")
            .withSandboxDestination()
            .build();


    String payload = APNS.newPayload().alertBody("Can't be simpler than this!").build();
    String token = "theTokenIsRemoveHere";
    service.push(token, payload);

And here is the error:

Exception in thread "main" com.notnoop.exceptions.InvalidSSLConfig: java.io.IOException: toDerInputStream rejects tag type 45
    at com.notnoop.apns.internal.Utilities.newSSLContext(Utilities.java:102)
    at com.notnoop.apns.ApnsServiceBuilder.withCert(ApnsServiceBuilder.java:161)
    at com.notnoop.apns.ApnsServiceBuilder.withCert(ApnsServiceBuilder.java:124)
    at com.geomobsters.cli.ApnsClient.main(ApnsClient.java:12)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.io.IOException: toDerInputStream rejects tag type 45
    at sun.security.util.DerValue.toDerInputStream(DerValue.java:806)
    at com.sun.net.ssl.internal.pkcs12.PKCS12KeyStore.engineLoad(PKCS12KeyStore.java:1201)
    at java.security.KeyStore.load(KeyStore.java:1185)
    at com.notnoop.apns.internal.Utilities.newSSLContext(Utilities.java:87)
    ... 8 more

Java APNS is expecting the cert as .p12 file.

You have to check both privatekey and certificate in your keychain. then right click-> "export 2 files" and export them you have to give it a password, this password you have to type here

.withCert("gpk.pem", "XXXX")

as your XXXX

good luck

EDIT:

.P12 – PKCS#12, contains certificates an private keys saved with a password .PEM – is Base64-encoded certificate, lockedby „-----BEGIN CERTIFICATE-----“ and „-----END CERTIFICATE-----“