Program: 163954
Project: 163954
Buggy source:
@Override public void paint(Level level){
  Painter.fill(level,this,Terrain.WALL);
  Rect c=getConnectionSpace();
  if (connected.size() <= 3) {
    for (    Door door : connected.values()) {
      Point start;
      Point mid;
      Point end;
      start=new Point(door);
      if (start.x == left)       start.x+=2;
 else       if (start.y == top)       start.y+=2;
 else       if (start.x == right)       start.x-=2;
 else       if (start.y == bottom)       start.y-=2;
      int rightShift;
      int downShift;
      if (start.x < c.left)       rightShift=c.left - start.x;
 else       if (start.x > c.right)       rightShift=c.right - start.x;
 else       rightShift=0;
      if (start.y < c.top)       downShift=c.top - start.y;
 else       if (start.y > c.bottom)       downShift=c.bottom - start.y;
 else       downShift=0;
      if (door.x == left || door.x == right) {
        mid=new Point(start.x + rightShift,start.y);
        end=new Point(mid.x,mid.y + downShift);
      }
 else {
        mid=new Point(start.x,start.y + downShift);
        end=new Point(mid.x + rightShift,mid.y);
      }
      Painter.drawLine(level,start,mid,Terrain.WATER);
      Painter.drawLine(level,mid,end,Terrain.WATER);
    }
  }
 else {
    ArrayList<Point> pointsToFill=new ArrayList<>();
    for (    Point door : connected.values()) {
      Point p=new Point(door);
      if (p.y == top) {
        p.y+=2;
      }
 else       if (p.y == bottom) {
        p.y-=2;
      }
 else       if (p.x == left) {
        p.x+=2;
      }
 else {
        p.x-=2;
      }
      pointsToFill.add(p);
    }
    ArrayList<Point> pointsFilled=new ArrayList<>();
    pointsFilled.add(pointsToFill.remove(0));
    Point from=null, to=null;
    int shortestDistance;
    while (!pointsToFill.isEmpty()) {
      shortestDistance=Integer.MAX_VALUE;
      for (      Point f : pointsFilled) {
        for (        Point t : pointsToFill) {
          int dist=distanceBetweenPoints(f,t);
          if (dist < shortestDistance) {
            from=f;
            to=t;
            shortestDistance=dist;
          }
        }
      }
      fillBetweenPoints(level,from,to,Terrain.WATER);
      pointsFilled.add(to);
      pointsToFill.remove(to);
    }
  }
  for (  Point p : getPoints()) {
    int cell=level.pointToCell(p);
    if (level.map[cell] == Terrain.WATER) {
      for (      int i : PathFinder.NEIGHBOURS8) {
        if (level.map[cell + i] == Terrain.WALL) {
          Painter.set(level,cell + i,Terrain.EMPTY);
        }
      }
    }
  }
  for (  Door door : connected.values()) {
    door.set(Door.Type.UNLOCKED);
  }
}

Fixed version (ground truth):
@Override public void paint(Level level){
  Painter.fill(level,this,Terrain.WALL);
  Rect c=getConnectionSpace();
  if (connected.size() <= 2) {
    for (    Door door : connected.values()) {
      Point start;
      Point mid;
      Point end;
      start=new Point(door);
      if (start.x == left)       start.x+=2;
 else       if (start.y == top)       start.y+=2;
 else       if (start.x == right)       start.x-=2;
 else       if (start.y == bottom)       start.y-=2;
      int rightShift;
      int downShift;
      if (start.x < c.left)       rightShift=c.left - start.x;
 else       if (start.x > c.right)       rightShift=c.right - start.x;
 else       rightShift=0;
      if (start.y < c.top)       downShift=c.top - start.y;
 else       if (start.y > c.bottom)       downShift=c.bottom - start.y;
 else       downShift=0;
      if (door.x == left || door.x == right) {
        mid=new Point(start.x + rightShift,start.y);
        end=new Point(mid.x,mid.y + downShift);
      }
 else {
        mid=new Point(start.x,start.y + downShift);
        end=new Point(mid.x + rightShift,mid.y);
      }
      Painter.drawLine(level,start,mid,Terrain.WATER);
      Painter.drawLine(level,mid,end,Terrain.WATER);
    }
  }
 else {
    ArrayList<Point> pointsToFill=new ArrayList<>();
    for (    Point door : connected.values()) {
      Point p=new Point(door);
      if (p.y == top) {
        p.y+=2;
      }
 else       if (p.y == bottom) {
        p.y-=2;
      }
 else       if (p.x == left) {
        p.x+=2;
      }
 else {
        p.x-=2;
      }
      pointsToFill.add(p);
    }
    ArrayList<Point> pointsFilled=new ArrayList<>();
    pointsFilled.add(pointsToFill.remove(0));
    Point from=null, to=null;
    int shortestDistance;
    while (!pointsToFill.isEmpty()) {
      shortestDistance=Integer.MAX_VALUE;
      for (      Point f : pointsFilled) {
        for (        Point t : pointsToFill) {
          int dist=distanceBetweenPoints(f,t);
          if (dist < shortestDistance) {
            from=f;
            to=t;
            shortestDistance=dist;
          }
        }
      }
      fillBetweenPoints(level,from,to,Terrain.WATER);
      pointsFilled.add(to);
      pointsToFill.remove(to);
    }
  }
  for (  Point p : getPoints()) {
    int cell=level.pointToCell(p);
    if (level.map[cell] == Terrain.WATER) {
      for (      int i : PathFinder.NEIGHBOURS8) {
        if (level.map[cell + i] == Terrain.WALL) {
          Painter.set(level,cell + i,Terrain.EMPTY);
        }
      }
    }
  }
  for (  Door door : connected.values()) {
    door.set(Door.Type.UNLOCKED);
  }
}