Convert a list of array into an array of array

The following snippet shows a solution:

// create a linked list
List<String[]> arrays = new LinkedList<String[]>();

// add some trivial test data (note: arrays with different lengths)
arrays.add(new String[]{"a", "b", "c"});
arrays.add(new String[]{"d", "e", "f", "g"});

// convert the datastructure to a 2D array
String[][] matrix = arrays.toArray(new String[0][]);

// test output of the 2D array
for (String[] s:matrix)
  System.out.println(Arrays.toString(s));

Try it on ideone

You could use toArray(T[]).

import java.util.*;
public class Test{
    public static void main(String[] a){ 
        List<String[]> list=new ArrayList<String[]>();
        String[][] matrix=new String[list.size()][];
        matrix=list.toArray(matrix);
    }   
}

Javadoc

Let us assume that we have a list of 'int' array.

List<int[]> list = new ArrayList();

Now to convert it into 2D array of type 'int', we use 'toArray()' method.

int result[][] = list.toArray(new int[list.size()][]);

We can generalize it further like-

List<T[]> list = new ArrayList();
T result[][] = list.toArray(new T[list.size()][]);

Here, T is the type of array.