(Java) Auto-Generate or Explicitly Specify the Message-ID Email Header

Demonstrates how to auto-generate or explicitly specify the Message-ID header field.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    CkEmail email = new CkEmail();
    boolean success;

    email.put_Subject("test");
    email.put_Body("test");
    email.AddTo("Joe","joe@example1.com");
    email.put_From("mary@example2.com");

    CkMailMan mailman = new CkMailMan();

    // When the mailman sends email, it renders the email to be sent,
    // and then sends the rendered MIME.

    // Instead of actually sending the email, this example will render
    // to MIME so we can see what would be sent..

    // We can explicitly set the Message-ID like this:
    mailman.put_AutoGenMessageId(false);
    email.AddHeaderField("Message-ID","<xyz123@abc>");

    String mimeStr = mailman.renderToMime(email);
    System.out.println(mimeStr);

    // This is what we get:

    // MIME-Version: 1.0
    // Date: Mon, 20 Jul 2020 17:20:09 -0500
    // Message-ID: <xyz123@abc>
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    // Content-Transfer-Encoding: 7bit
    // X-Priority: 3 (Normal)
    // Subject: test
    // To: Joe <joe@example1.com>
    // From: mary@example2.com
    // 
    // test

    System.out.println("--------");

    // If we auto-generate...
    mailman.put_AutoGenMessageId(true);
    mimeStr = mailman.renderToMime(email);
    System.out.println(mimeStr);

    // We get this:

    // MIME-Version: 1.0
    // Date: Mon, 20 Jul 2020 17:21:20 -0500
    // Message-ID: <04EDE096BBFE484967F6398A973B0FCF6EA09A44@CHILKATSLICE>
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    // Content-Transfer-Encoding: 7bit
    // X-Priority: 3 (Normal)
    // Subject: test
    // To: Joe <joe@example1.com>
    // From: mary@example2.com
    // 
    // test
  }
}