Java 8 reduce code example
Understanding Java 8 Reduce function
Combine by key to find max
Use combine by key and use map transformation to find Max value for all the keys in Spark
group by key
Group by key and in the Map Partition apply some custom logic on the aggregated values of the key in Spark
accumulate all values for a given key in spark
For a given key collect all the values, which can be later use for applying some custom logic like ( average , max , min, top n, expression evaluation) in Spark