### Question:
MailItem { public List<String> getReceivers() { return receivers; } MailItem();  MailItem(String title, String body, DataSource attachments, String sender, String... receivers);  MailItem(String title, String body, DataSource attachments, String sender, List<String> receivers);  MailItem(String title, String body, List<DataSource> attachments, String sender, String... receivers);  MailItem(String title, String body, List<DataSource> attachments, String sender, List<String> receivers); String getId(); void setId(String id); String getTitle(); void setTitle(String title); String getBody(); void setBody(String body); List<DataSource> getAttachments(); void setAttachments(List<DataSource> attachments); String getSender(); void setSender(String sender); List<String> getReceivers(); void setReceivers(String... receivers); void setReceivers(List<String> receivers); MailEvent getEvent(); void setEvent(MailEvent event); Map<String, String[]> getHeaders(); void setHeaders(Map<String, String[]> headers); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void getReceivers() throws Exception { List<String> receivers = new LinkedList<>(); receivers.add("receiver1"); receivers.add("receiver2"); item.setReceivers(receivers); assertEquals(receivers, item.getReceivers()); receivers.add("receiver3"); item.setReceivers("receiver1", "receiver2", "receiver3"); assertEquals(receivers, item.getReceivers()); }