Copying array values without creating just a reference.

How do you copy the values of one array to another without the 2nd array just being a reference to the first? I need to be able to copy an array and modify the original without those modifications getting passed to the copy.

here's my code

Code:

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// there's a matrix of Doubles called columns: the one I want to copy
for (int i = 0; i < rowlength ; i++) {
            for (int e = 0; e < rowlength ; e++) {
            //copy
                Double d= new Double(columns[i][e]);
                prevcolumns[i][e]=new Double(d.doubleValue());
            }

        }


for (int i = 0; i < size; i++) {
            for (int e = 0; e < size; e++) {
             
                columns[30 + i][30 + e] += 1;

            }

        }
// for any columns[i][e] it is the same as prevcolumns[i][e]... which is bad

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thanks for any thoughts

Nevermind sorry lol