title: Adding data to a hashmap from on apache-spark RDD operation (Java)
body: <p>I've used a map step to create a JavaRDD object containing some objects I need. Based on those objects I want to create a global hashmap containing some stats, but I can't figure out which RDD operation to use. At first I thought reduce would be the solution, but then I saw that you have to return the same type of objects. I'm not interested in reducing the items, but in gathering all the stats from all the machines (they can be computed separately and then just added up_.</p>
  
  <p>For example:
  I have an RDD of Objects containing an integer array among other stuff and I want to compute how many times each of the integers has appeared in the array by putting them into a hashtable. Each machine should compute it's own hashtable and then put them all in one place in the driver.</p>