title: Associate multiple values with the single key and also maintain the order of values
body: <p>I have a class which contain the following members</p>
  
  <pre><code>private String patientName;
  private String patientPhoneNumber;
  </code></pre>
  
  <p>now I have multiple names attached with the phone No. for example</p>
  
  <pre><code>1234567, AAA
  1234567, BBB
  8765432, CCC
  8765432, GGG
  </code></pre>
  
  <p>Now I want to store them in a Map but the phone No. should be the key having multiple values, for 1234567 i should have value AAA and BBB, please advise how can I store the multiple values with the single key in map here my key is Phone No. and then please let me know if I want to print in console then ow would I iterate over the Map</p>
  
  <p>Also please not that I want to maintain the order also let say first I get the value AAA and then BBB so i should maintain these order also, since I get this is just a example but in my scenario I will be getting this value from backend so to maintain the order is also necessary please advise.</p>