Merge Interval (two-dimensional array with the list of conversion)

public int[][] merge(int[][] intervals) {
        The ArrayList < int []> = RES new new the ArrayList <> ();
         IF (intervals.length <2) return Intervals;
　　　　  // rewrite collation 　　　　negative return value is a parameter indicating a <parameter b, is positive and vice versa 
        Arrays.sort (Intervals, new new Comparator < int []> () {
             public  int Compare ( int [] A, int [] B) {
                 IF (A [0] == B [0 ]) {
                     return A [. 1] - B [ 1 ];
                }else {
                    return a[0] - b[0];
                }
            }
        });
        for (int i = 1; i < intervals.length; i++) {
            if (intervals[i][0]<=intervals[i-1][1]){
                intervals [i][0]=intervals[i-1][0];
                intervals [i][1]=Math.max(intervals[i][1],intervals[i-1][1]);
                intervals[i-1]= null;
            }
        }
        int i = 0;
        for (int[] a:intervals) {
            if (a!=null)
                res.add(a);

        }

        return res.toArray(new int[0][0]);

    }

Using list.toArray (T [] a) Method

E.g:

List<double[]>转double[][]

List<double[]>list=new ArrayList<double[]>();
list.add(new double[]{10.0,12.0});
list.add(new double[]{11.0,32.0});
double[][]result=list.toArray(new double[0][0]);