Passing values from ArrayList to 2D-Array

I created an ArrayList to store values:

ArrayList <Long> longList = new ArrayList<Long>();

But when I try to pass the values to a 2D-Array there is a problem. In the first column I want my results, so the length it may change depending on the list, but the second column I want only 1 row.

public static long[][] deco(long num) {
    long[][] ans = new long[longList.size()][1];

    for (int j=0; j < longList.size() ; j++)  {
        ans[j][0] = longList.get(j);  
    ans[0][1] = remaining;
    return ans;

So when I return the Array and see if it worked it gives me a weird number, but when I return the ArrayList the correct numbers are in. For an example the right answer should be [4,2][1] but I get [[J@15db9742