title: Java APNS (Apple Push Notification Service) error
body: <p>I am trying to use Java APNS - an open source project - to send push notifications to iPhones.
  I am getting an error, though. </p>
  
  <p>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.</p>
  
  <p>Here is the code:</p>
  
  <pre><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);
  </code></pre>
  
  <p>And here is the error:</p>
  
  <pre><code>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
  </code></pre>