title: how to implement below data structure in java using collection framework
body: <p>I have below data structure like this </p>
  
  <pre><code>Country,StateID1 where StateID1 contains "City1","City2","City3" etc
  Country,StateID2 where StateID2 contains "City1","City2","City3" etc
  </code></pre>
  
  <p>I know i can't use HashMap to implement above data structure because if i add StateID2 to same Country StateID1 will be replace with StateID2
  for eg </p>
  
  <pre><code>map.put("1","1111");
  map.put("1","2222");
  output
  
   key:value
   1:2222`
  </code></pre>
  
  <p>i am facing hard time to figure out how to do this. I need some support from you guys</p>