How to create Object array in Java Dynamically

Question

I want to create an object something like this and set the value using utils -

I tried with - Utils -

ArrayList<Map<String, ArrayList<String>>> constructObj = new ArrayList<Map<String, ArrayList<String>>>();

[
    {
        "userName": "",
        "userEmail": "",
        "c1": [],
        "c2": []
    }, 
    {
        "userName": "",
        "userEmail": "",
        "c1": [],
        "c2": []
    }, 
]

Not able to set the result of userName and userEmail. Any idea ? I am new to Java Spring boot.