Rotten oranges

Input: mat[][] = 
[[0, 1, 2], 
[0, 1, 2], 
[2, 1, 1]]
Output: 1
Explanation: Oranges at positions (0,2), (1,2), (2,0) will rot oranges at (0,1), (1,1), (2,2) and (2,1) in unit time.

class Solution {
    public int orangesRotting(int[][] grid) {
        int n = grid.length;
        int m = grid[0].length;
        int fresh=0;
        Queue<int[]> q = new LinkedList<>();

        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(grid[i][j]==2){
                    q.add(new int[]{i,j});
                }
                else if(grid[i][j]==1){
                    fresh++;
                }
            }
        }

        if(fresh==0){
            return 0;
        }

        int minutes=0;
        int dir[][] = {{-1,0},{1,0},{0,-1},{0,1}};

        while(!q.isEmpty()){
            int size = q.size();
            boolean hasrotten = false;

            for(int i=0;i<size;i++){
                int curr[] = q.remove();
                int x = curr[0];
                int y = curr[1];

                for(int dirr[] : dir){
                    int nx = x+dirr[0];
                    int ny = y+dirr[1];

                    if(nx>=0 && nx<n && ny>=0 && ny<m && grid[nx][ny]==1){
                        grid[nx][ny]=2;
                        q.add(new int[]{nx,ny});
                        fresh--;
                        hasrotten = true;
                    }
                }
            }
            if(hasrotten){
                minutes++;
            }
        }
        return fresh==0 ? minutes : -1;
    }
}