What is the best way to implement receiving API data through 3 different sources?

Question

Java

What is the best way to implement receiving API data through 3 different sources?
For example, in the first source 14000, in the second 1500, in the third 1500.
I get data at 50 per page.
I want to combine all 3 sources into 1 tape (ListView) sorted by date. From newest to oldest. When receiving information, there is a date in this form: 2016-03-07 23:44:06
Actually the question is how to connect? From what came to mind is:
- parse all the data, write to the local database and then sort and work with the database ?!
How logical is this, or are there other options?

Answer 1

rxjava for ease of writing
And sorting is not necessary in the base