Refer below documents for explanation::
https://medium.com/@kpraga/how-to-convert-database-results-to-java-object-to-json-files-ae2df119ab65 https://medium.com/@kpraga/how-to-merge-separate-json-files-into-a-single-array-of-json-while-reading-data-from-a-database-035a59f72d1f