title: Java 8 stream sum and count at once
body: <p>How can I use Java 8 streams to calculate an average of the stream elements? 
  Because I cannot use a stream twice I have to do it in one iteration. 
  The stream contains custom beans holding a float value. The number of elements in the stream may vary.
  Hence, I want to sum up the float value of all elements in the stream and divide it by the number of elements in the stream.</p>
  
  <p><strong>Update:</strong>
  Finally I need the sum of all elements in the stream as well a the average of all elemnts of the stream.</p>