title: Search if specified key and value exists
body: <p>I am working with hashmap datastructure in java. I have some data in which each entry(value) has a group(key). Now i am storing this data in hashmap as follows</p>
  
  <pre><code>HashMap&lt;Integer, String&gt; map = new HashMap&lt;Integer, String&gt;();
  map.put(1, "value1");
  map.put(1, "value2");
  map.put(2, "value3");
  map.put(2, "value4");
  map.put(3, "value5");
  map.put(3, "value6");
  map.put(3, "value7");
  </code></pre>
  
  <p>now I want to search if entry (with key=3 and value="value6") exists in map or not. Is there any specific method to call? or is there and other way to do it?</p>