title: Validate APN push token
body: <p>I have a server side java application which send bulk push messages to apple server. Recently i'm getting multiple <strong>SSLSocketException: Connection closed by remote host</strong> OR <strong>SSLSocketException: Broken pipe expcetions.</strong>  </p>
  
  <p>I understand that in case i'm sending invalid tokens, apple forcefully closes the connection. I also have a feedback loop, but the failing tokens never appear on feedback loop since they are not even accepted by apple. </p>
  
  <p>Is there any algorithm or method to know, why the device token is "invalid" ?</p>