Append to 2-dimensional array
String[][] headings = new String[][] { {
        "three",
        "three",
        "three"
               } };

String[][] headings = new String[][] { {
    "three",
    "three",
    "three"
           }, {} }; // note placeholder for to-be-added triplet.
     String val = condition ? "one": "two";
     headings[1] = new String[] {val, val, val};

ArrayList<String[]> headings = new ArrayList<String[]>();
headings.add(new String[] { "three", "three", "three" });

if(/* condition */)
    headings.add(new String[] { "two", "two", "two" });
else
    headings.add(new String[] { "one", "one", "one" });