How to read in a file of numbers into an array list in Java -

i want able read in map file looks like:

0, 0, 0, 0, 0

0, 0, 1, 0, 0

0, 1, 1, 1, 1

0, 1, 1, 1, 0

0, 0, 1, 1, 0

and create array list looks like:

{[0, 0, 0, 0, 0],

[0, 0, 1, 0, 0],

[0, 1, 1, 1, 1],

[0, 1, 1, 1, 0],

[0, 0, 1, 1, 0]}

i have tried using br.readline() appears getting stuck not throwing error in middle.

public static int[][] loadfile() throws ioexception{

    filereader in = new filereader(main.currentfilepath + main.currentfile);     bufferedreader br = new bufferedreader(in);     string line;     int [] intarray = {};     int [][] filearray = {};     int j = 0;     while ((line = br.readline()) != null) {         list<string> stringlist = new arraylist<string>(arrays.aslist(line.split(",")));         string[] stringarray = stringlist.toarray(new string[0]);         list<integer> intlist = new arraylist<integer>();         system.out.println("rrrrr");         for(int = 0; < stringlist.size(); i++) {             scanner scanner = new scanner(stringarray[i]);             system.out.println("ggggg");             while (scanner.hasnextint()) {                 intlist.add(scanner.nextint());                 intarray = intlist.parallelstream().maptoint(integer::intvalue).toarray();                 system.out.println("ffff");             }             system.out.println(filearray[j][i]);             filearray[j][i] = intarray[i];         }         j++;     }     return filearray;  } 

the basic problem is, you're declaring array of 0 length (no elements), makes impossible add elements it.

int [][] filearray = {}; 

unless know in advance number of rows/columns need, arrays not helpful, instead, make use of list of kind, example...

list<int[]> rows = new arraylist<>(5); int maxcols = 0; try (bufferedreader br = new bufferedreader(new filereader(new file("test.txt")))) {     string text = null;     while ((text = br.readline()) != null) {         system.out.println(text);         string[] parts = text.split(",");         int[] row = new int[parts.length];         maxcols = math.max(maxcols, row.length);         (int col = 0; col < parts.length; col++) {             row[col] = integer.parseint(parts[col].trim());         }         rows.add(row);     } } catch (ioexception ex) {     ex.printstacktrace(); }  int[][] map = new int[rows.size()][maxcols]; (int row = 0; row < rows.size(); row++) {     map[row] = rows.get(row); } 

my "personal" gut feeling not bother arrays @ , make use of compound lists...

list<list<integer>> rows = new arraylist<>(5); try (bufferedreader br = new bufferedreader(new filereader(new file("test.txt")))) {     string text = null;     while ((text = br.readline()) != null) {         system.out.println(text);         string[] parts = text.split(",");         list<integer> row = new arraylist<>(parts.length);         (string value : parts) {             row.add(integer.parseint(value.trim()));         }         rows.add(row);     } } catch (ioexception ex) {     ex.printstacktrace(); }