*Help me* Processing 2048 keypressed

I'm in the middle of an final project in Programming and I have a tiny problem with my keypressed. My blocks won't always connect when two blocks are side by side.

I've only tried coding the UP key but I guess it doesn't matter. Here's the code:

int[][] bane = new int[4][4];
int score = 0;
int afstand = 20;
int felt = 125;
int randX;
int randY;
int countSpawn = 0;

void setup() 
{
  size(600, 600);
  background(255);
  for (int i = 0; i < 4; i++) {
    for (int n = 0; n < 4; n++) {
      bane[i][n] = 0;
    }
  }
  spawn();
  spawn();
}

void spawn()
{
  countSpawn = 0;
  for (int i = 0; i < 4; i++) {
    for (int n = 3; n >= 0; n--) {
      if (bane[i][n] == 0) {
        countSpawn++;
      }
    }
  }
  if (countSpawn <= 0) {
    return;
  }
  int randX = (int)random(4);
  int randY = (int)random(4);
  if (bane[randX][randY] != 0) {
    spawn();
  } else {
    bane[randX][randY] = 2;
  }
}

void draw()
{
  fill(187,173,160);
  noStroke();
  rect(0,0,600,600,15); 

  for(int i = 0; i < 4; i++) 
  {
    for(int j = 0; j < 4; j++)
    {

      fill(205,193,179);
      rect(145*i+20,145*j+20,125,125,10);

      if (bane[i][j] > 0)
      {
        textAlign(CENTER);
        textSize(40);
        fill(0);
        text(bane[i][j], i*145+82.5, j*145+92.5);
      }
    }
  } 
}

void keyPressed() {   
  if (key == CODED) { 
    if (keyCode == UP) {
      for (int i = 0; i < 4; i++) {
        for (int n = 3; n > 0; n--) {
          if (bane[i][n] != 0) {
            if (bane[i][n-1] == 0) {
              bane[i][n-1] = bane[i][n];
              bane[i][n] = 0;
            } else {
              if (bane[i][n-1] == bane[i][n]) {
                bane[i][n-1] = bane[i][n]*2;
                bane[i][n] = 0;
              }
              break;
            }
          }
        }
      }
      spawn();
    } else if (keyCode == DOWN) {
    } else if (keyCode == LEFT) {
    } else if (keyCode == RIGHT) {
    }
  }

}