the most popular female first names in the United States

Here is a sample of the most popular female first names in the United States
according to the 1990 census.
String PopularName
="MARY,PATRICIA,LINDA,BARBARA,ELIZABETH,JENNIFER,MARIA,SUSAN,MARGARET’D
OROTHY,LISA,NANCY,KAREN,BETTY,HELEN,SANDRA,DONNA,CAROL,RUTH,SHARON,
MICHELLE,LAURA,SARAH,KIMBERLY,DEBORAH,JESSICA,SHIRLEY,CYNTHIA,ANGELA,ME
LISSA,BRENDA,AMY,ANNA,REBECCA,VIRGINIA,KATHLEEN,PAMELA,MARTHA,DEBRA,A
MANDA,STEPHANIE,CAROLYN,CHRISTINE,MARIE,JANET,CATHERINE,FRANCES,ANN,JOY
CE,DIANE,ALICE,JULIE,HEATHER,TERESA,DORIS,GLORIA,EVELYN,JEAN,CHERYL,MILDR
ED,KATHERINE,JOAN,ASHLEY,JUDITH,ROSE";
I want you to do the following:
1. Convert this comma delimited list into ArrayList
2. Sort an ArrayList using merge sort algorithm along with a recursion
3. Find initial of each name and then find the occurrences of each the alphabet and
store the result in appropriate Java collections , set, map, or something else and
justify why you chose this collection
4. I want you to print the result of the initial of each names along with it occurrences
and it should show something like this:
Letter | Occurrence
M|7
B|3
5. When you have the collection you created in step 3 ready, can change the capital
letter into small letter and we you print the result it should be:
Letter | Occurrence
m|7
b|3
6. Can you accomplish step 1 & 2 by just using one of the Java collections assuming
that you are looping and fetching every name putting it in this collection and it is
going to be sorted automatically? Write how you are going to do it.