Casting exception transforming Lists to Arrays

Question

I would like to build an array of arrays starting from a list, but I get a casting exception. Anybody knows why? Here is the code

List<String[]> listofarray=new ArrayList<String[]>();
//...filling the list...
String[][] ob= (String[][]) listofarray.toArray();

Answer 1

List#toArray() method without any argument returns an Object[] . You need to use the overloaded generic version - List#toArray(T[]) passing String[][] as argument. Then you wouldn't need to cast the result back.

String[][] ob= listofarray.toArray(new String[listofarray.size()][]);