Update LessThan7.java

src/main/java/LessThan7.java

@@ -8,6 +8,7 @@ import java.util.concurrent.RecursiveTask;
  * Your code must have O(n) work, O(lg(n)) span, where n is the length of arr
  */
 public class LessThan7 {
+    // Its static so that the compiler knows to not duplicate memory when we fork.
     private static final ForkJoinPool POOL = new ForkJoinPool();
     private static final int CUTOFF = 1;
 
@@ -22,6 +23,7 @@ public class LessThan7 {
         return POOL.invoke(new LessThan7Task(arr, 0, arr.length));
     }
 
+    // Static for the same reasons above
     private static class LessThan7Task extends RecursiveTask<Integer> {
         int[] arr;
         int lo, hi;