title: NullPointerException with non-null <key,value> pair in hashtable
body: <p>I get a null pointer exception with a hashtable 'get' method call. The key is definitely not null. I checked at 'check1'(commented in the code) by prining the value of the variable item. I have valid list of strings. I still get a null pointer exception. What am I doing wrong ?     </p>
  
  <pre><code>       List&lt;String&gt; l= new ArrayList&lt;String&gt;();
              //Values added to l;
              Hashtable&lt;String,int&gt; h=new Hashtable&lt;String,int&gt;();
  
              for(int i=0;i&lt;l.size();i++){
                  String item= l.get(i);
                  //check1
                  int value= h.get(item); //exception arises at this point
                  h.put(item,++value);
              }
  </code></pre>