Program: 10458
Project: 10458
Buggy source:
private void updateVisibleAnnotations(){
  System.out.println("String_Node_Str");
  final float marginFactor=2.0f;
  final float bucketSize=60.0f;
  MKMapRect visibleMapRect=mapView.getVisibleMapRect();
  MKMapRect adjustedVisibleMapRect=visibleMapRect.inset(-marginFactor * visibleMapRect.getSize().getWidth(),-marginFactor * visibleMapRect.getSize().getHeight());
  CLLocationCoordinate2D leftCoordinate=mapView.convertPointToCoordinateFromView(CGPoint.Zero(),getView());
  CLLocationCoordinate2D rightCoordinate=mapView.convertPointToCoordinateFromView(new CGPoint(bucketSize,0),getView());
  double gridSize=MKMapPoint.create(rightCoordinate).getX() - MKMapPoint.create(leftCoordinate).getX();
  MKMapRect gridMapRect=new MKMapRect();
  gridMapRect.setSize(new MKMapSize(gridSize,gridSize));
  double startX=Math.floor(adjustedVisibleMapRect.getOrigin().getX() / gridSize) * gridSize;
  double startY=Math.floor(adjustedVisibleMapRect.getOrigin().getY() / gridSize) * gridSize;
  double endX=Math.floor((adjustedVisibleMapRect.getOrigin().getX() + adjustedVisibleMapRect.getSize().getWidth()) / gridSize) * gridSize;
  double endY=Math.floor((adjustedVisibleMapRect.getOrigin().getY() + adjustedVisibleMapRect.getSize().getHeight()) / gridSize) * gridSize;
  gridMapRect.getOrigin().setY(startY);
  while (gridMapRect.getOrigin().getY() <= endY) {
    gridMapRect.getOrigin().setX(startX);
    while (gridMapRect.getOrigin().getX() <= endX) {
      NSSet<NSObject> allAnnotationsInBucket=allAnnotationsMapView.getAnnotations(gridMapRect);
      NSSet<NSObject> visibleAnnotationsInBucket=mapView.getAnnotations(gridMapRect);
      if (allAnnotationsInBucket == null || visibleAnnotationsInBucket == null)       continue;
      List<PhotoAnnotation> filteredAnnotationsInBucket=new ArrayList<>();
      for (      NSObject annotation : allAnnotationsInBucket) {
        if (annotation instanceof PhotoAnnotation) {
          filteredAnnotationsInBucket.add((PhotoAnnotation)annotation);
        }
      }
      if (filteredAnnotationsInBucket.size() > 0) {
        PhotoAnnotation annotationForGrid=getAnnotationInGrid(gridMapRect,filteredAnnotationsInBucket);
        filteredAnnotationsInBucket.remove(annotationForGrid);
        annotationForGrid.setContainedAnnotations(filteredAnnotationsInBucket);
        mapView.addAnnotation(annotationForGrid);
        for (        final PhotoAnnotation annotation : filteredAnnotationsInBucket) {
          annotation.setClusterAnnotation(annotationForGrid);
          annotation.setContainedAnnotations(null);
          if (visibleAnnotationsInBucket.contains(annotation)) {
            final CLLocationCoordinate2D actualCoordinate=annotation.getCoordinate();
            UIView.animate(0.3,new Runnable(){
              @Override public void run(){
                annotation.setCoordinate(annotation.getClusterAnnotation().getCoordinate());
              }
            }
,new VoidBooleanBlock(){
              @Override public void invoke(              boolean v){
                annotation.setCoordinate(actualCoordinate);
                mapView.removeAnnotation(annotation);
              }
            }
);
          }
        }
      }
      gridMapRect.getOrigin().setX(gridMapRect.getOrigin().getX() + gridSize);
    }
    gridMapRect.getOrigin().setY(gridMapRect.getOrigin().getY() + gridSize);
  }
  System.out.println("String_Node_Str");
}

Fixed version (ground truth):
private void updateVisibleAnnotations(){
  System.out.println("String_Node_Str");
  final float marginFactor=2.0f;
  final float bucketSize=60.0f;
  MKMapRect visibleMapRect=mapView.getVisibleMapRect();
  MKMapRect adjustedVisibleMapRect=visibleMapRect.inset(-marginFactor * visibleMapRect.getSize().getWidth(),-marginFactor * visibleMapRect.getSize().getHeight());
  CLLocationCoordinate2D leftCoordinate=mapView.convertPointToCoordinateFromView(CGPoint.Zero(),getView());
  CLLocationCoordinate2D rightCoordinate=mapView.convertPointToCoordinateFromView(new CGPoint(bucketSize,0),getView());
  double gridSize=MKMapPoint.create(rightCoordinate).getX() - MKMapPoint.create(leftCoordinate).getX();
  MKMapRect gridMapRect=new MKMapRect();
  gridMapRect.setSize(new MKMapSize(gridSize,gridSize));
  double startX=Math.floor(adjustedVisibleMapRect.getOrigin().getX() / gridSize) * gridSize;
  double startY=Math.floor(adjustedVisibleMapRect.getOrigin().getY() / gridSize) * gridSize;
  double endX=Math.floor((adjustedVisibleMapRect.getOrigin().getX() + adjustedVisibleMapRect.getSize().getWidth()) / gridSize) * gridSize;
  double endY=Math.floor((adjustedVisibleMapRect.getOrigin().getY() + adjustedVisibleMapRect.getSize().getHeight()) / gridSize) * gridSize;
  gridMapRect.getOrigin().setY(startY);
  while (gridMapRect.getOrigin().getY() <= endY) {
    gridMapRect.getOrigin().setX(startX);
    while (gridMapRect.getOrigin().getX() <= endX) {
      Set<MKAnnotation> allAnnotationsInBucket=allAnnotationsMapView.getAnnotations(gridMapRect);
      Set<MKAnnotation> visibleAnnotationsInBucket=mapView.getAnnotations(gridMapRect);
      if (allAnnotationsInBucket == null || visibleAnnotationsInBucket == null)       continue;
      List<PhotoAnnotation> filteredAnnotationsInBucket=new ArrayList<>();
      for (      MKAnnotation annotation : allAnnotationsInBucket) {
        if (annotation instanceof PhotoAnnotation) {
          filteredAnnotationsInBucket.add((PhotoAnnotation)annotation);
        }
      }
      if (filteredAnnotationsInBucket.size() > 0) {
        PhotoAnnotation annotationForGrid=getAnnotationInGrid(gridMapRect,filteredAnnotationsInBucket);
        filteredAnnotationsInBucket.remove(annotationForGrid);
        annotationForGrid.setContainedAnnotations(filteredAnnotationsInBucket);
        mapView.addAnnotation(annotationForGrid);
        for (        final PhotoAnnotation annotation : filteredAnnotationsInBucket) {
          annotation.setClusterAnnotation(annotationForGrid);
          annotation.setContainedAnnotations(null);
          if (visibleAnnotationsInBucket.contains(annotation)) {
            final CLLocationCoordinate2D actualCoordinate=annotation.getCoordinate();
            UIView.animate(0.3,new Runnable(){
              @Override public void run(){
                annotation.setCoordinate(annotation.getClusterAnnotation().getCoordinate());
              }
            }
,new VoidBooleanBlock(){
              @Override public void invoke(              boolean v){
                annotation.setCoordinate(actualCoordinate);
                mapView.removeAnnotation(annotation);
              }
            }
);
          }
        }
      }
      gridMapRect.getOrigin().setX(gridMapRect.getOrigin().getX() + gridSize);
    }
    gridMapRect.getOrigin().setY(gridMapRect.getOrigin().getY() + gridSize);
  }
  System.out.println("String_Node_Str");
}