Solve the problem. ArrayList_Partition_GroupBy_Join

You need help with one of the tasks (Java). There are two entry lists. The challenge is this. Divide the first list into equal parts, the second-round-robin method. Further, each section contains one part of the first list and all parts of the second. It is necessary in each "section" to combine the lists (part of the first and the resulting parts of the second) according to some value.

I.E. Implementation of Parallel Join Algorithms "Divide &Broadcast (equal division)"