“Accumulators” are Spark’s offline debuggers.
Similar to “Hadoop Counters”, “Accumulators” provide the number of “events” in
a program.
Accumulators
are the variables that can be added through associative operations. Spark
natively supports accumulators of numeric value types and standard mutable
collections. “AggregrateByKey()” and “combineByKey()” uses accumulators.
