java Array Form Creation Question

Data type ArrayList Map String,Object

Result value

[0] "date" = 2019-08-0100:00:00", "work" : "work", "department" : "username" : "potato" > [1] "date" = 2019-08-0100:00:00", "work" : "work" , "department" : "username" : "sweet potato [2] "date" = 2019-08-0100:00:00", "work" : "work", "department" : "department", "username" : "moo"> [3] "date" = 2019-08-0200:00", "work" : "work", "department" : "department", "username" : "potato" >

I'd like to process it so that it comes out in the following format, so what should I do? ㅠ<

{ username: "Potato", department: "Department", schedule : [{date : 2019-08-0100:00:00, work : work }, {date : 2019-08-0200:00, work : work }] }