### Question:
ExtendedMimeMessage extends MimeMessage { public boolean isEmpty() { return this.dh == null; } ExtendedMimeMessage();  ExtendedMimeMessage(Session session, InputStream is);  ExtendedMimeMessage(MimeMessage source); static ExtendedMimeMessage wrap(MimeMessage message); boolean isEmpty(); void setType(String mailType); String getType(); void setMessageId(String messageId); boolean ensureSaved(); @Override void setHeader(String name, String value); String getUniqueMessageId();  }### Answer:
@Test public void isEmpty() throws Exception { ExtendedMimeMessage message = new ExtendedMimeMessage(); assertThat(message.isEmpty(), is(true)); message.setText(TEST_CONTENT); assertThat(message.isEmpty(), is(false)); }