Copy constructors instead of Clone

Computer Science
1

In Java, I’m attempting to build a copy constructor. I’m having trouble with the class’s non-primitive type fields. It is sharing the members while producing a new copy. As an example,

public class Bad implements Cloneable {
    private ArrayList<Integer> a;
    private Object c;

    public static void main(String[] args) {
        Bad b1 = new Bad();
        b1.a.add(10);

        System.out.println(b1.a);
        Bad b2 = b1.clone();
        b2.a.add(12);

        System.out.println(b1.a);   
    }

    Bad() {
        a = new ArrayList<>();
        c = null;
    }

    Bad(Bad b) {
        a = b.a;
        c = b.c;
    }

    public Bad clone() {
        return new Bad(this);
    }
}

As a result of this,

[10]
[10, 12]

This is not something I want to happen. Consider the following example given in here. My original issue has even more user-defined fields.
Or are there libraries that will perform the work for me? Thank you ahead of time.

2

I guess you could make a copy of the ArrayList

    Bad(Bad b) {
        a = new ArrayList<Integer>(b.a.size());
        a.addAll(b.a);
        c = b.c;
    }

but if its an ArrayList of objects, you’d need more code to make a copy of each thing in the ArrayList appropriately too.